Lose a Match and Still Win: How Round Robin Works at the Finals

There is a particular kind of confusion that only happens in November. A player you like loses a match. You watch them shake hands, towel off, sit down with their head in a towel. And then the commentator says, quite cheerfully, that they can still win the tournament.

If you have ever squinted at the television in that moment and thought, hang on, how — this is for you. For two weeks every year, tennis abandons the thing that defines it. The sport that spends ten months telling you that one bad afternoon ends your tournament suddenly says: no, have another go.

It is the round robin, and it is running right now.

Two events, one strange format

The WTA Finals start on Sunday 8 November at the Indian Wells Tennis Garden in California and run to 15 November. The ATP Finals pick up where they leave off, from 15 to 22 November at the Inalpi Arena in Turin, on an indoor hard court. Between them they account for the only two round-robin singles events on the entire calendar.

Everything else you have watched this year was a knockout. Lose in Melbourne, lose in Paris, lose at a Masters 1000 on a wet Tuesday in October, and you are on a plane. These two weeks are the exception, and they are the exception on purpose.

The shape is the same at both. Eight players. Two groups of four. Everybody plays everybody in their own group, which means three matches each, guaranteed, whatever happens. The top two from each group go through to the semifinals. From there it reverts to normal: win or go home, semifinal, final, done.

At Indian Wells that puts Elena Rybakina, Coco Gauff, Jessica Pegula and Linda Noskova in one group, with Aryna Sabalenka, Mirra Andreeva, Elina Svitolina and Karolina Muchova in the other. Rybakina opens against Noskova; Gauff plays Pegula straight after. Rybakina arrives as the defending champion and as the world number one, having finished the year on top of the rankings for the first time in her career — the seventeenth woman to do it — after winning both the Australian Open and the US Open. Muchova took the last place in the field.

Turin was still being settled as the Paris Masters finished. Alexander Zverev, Carlos Alcaraz, Ben Shelton, Daniil Medvedev and Flavio Cobolli had places. The remaining chairs were being argued over by a handful of men with a week of tennis left, which is its own kind of entertainment, and we wrote about that scramble in the race to Turin.

Why anybody would do it this way

The simple answer is that a knockout draw of eight would be over in three days and half the field would play once.

Think about that from the cheap seats. You have saved up, flown somewhere, bought a ticket to see the eight best players in the world. In a knockout, four of them lose on day one and you may never see them again. Round robin guarantees that every single player you came for plays three times. Nobody travels across a continent to watch one match and a long goodbye.

It is also, quietly, the fairest thing the sport does. Tennis is brutal about variance. A knockout draw lets a bad toss, a blister, a windy Tuesday or one tight tie-break erase a player who has been the best in the world for eleven months. Give everyone three matches and the noise gets quieter. The player who has genuinely been superb tends to survive a single off day. That is the bargain: more tennis for you, more justice for them.

The cost of the bargain is complication. And the complication is where it gets good.

How the eight get split up

The draw is not random in the way a first-round Grand Slam draw is random. The eight qualifiers are seeded on ranking, and the top two are kept in separate groups, so the best two players in the world cannot possibly meet before the semifinals. The other six are drawn around them.

That one decision shapes the entire week. It means each group has an obvious favourite and three players who have to take something off somebody. It also means the group without the top seed frequently turns into the harder one, because the quality is flatter, the matches are closer, and nobody can afford a slow Monday.

The women have used this shape, with one interruption, since the round-robin format came back in 2003. It has survived a long run of moves between cities and continents without changing in any meaningful way: eight players, two groups, three matches each. Whatever else is different about the season finale in a given year — the time zone, the altitude, the colour of the court, the size of the cheque — that skeleton stays the same.

When everybody finishes level

Three matches each means a group can end in almost any arrangement. Someone might go 3-0. More often two or three players finish on the same number of wins, and then the sport has to produce an answer from somewhere.

The ladder is the same for the women and the men, and it is worth knowing, because every November it decides somebody's season.

First, number of wins. Obvious enough.

Second, if exactly two players are level, the head-to-head between them. Also obvious. You beat them, you go through, nothing else matters.

Third, if three players are level, the percentage of sets won across all three of their matches.

Fourth, if that still has not separated them, the percentage of games won.

Fifth, and only if the sport has genuinely run out of ideas, the rankings.

Read those last three again and you will understand why, in the middle of the second week, you start seeing players who have already won a set look agitated about losing the next one 6-4 rather than 6-3. They are not being precious. They are counting.

The three-way tie, where it gets genuinely odd

Here is the scenario that produces all the drama, and the one worth understanding properly, because it comes around more often than you would think.

Imagine a group where the top seed wins the first two matches and then loses the last one. The other three players each beat one of the others. Nobody is on three wins. Three players are sitting on one win and two losses, and only one semifinal place is left.

This is not a hypothetical worked out for a rulebook. Groups fall apart like this fairly regularly, because the eight players are close to each other in quality and because the third match of a group is often played by somebody with nothing left to win.

Now the percentages start. Sets first: every set the three tied players have won, as a proportion of every set they have played. If one of them took a set off the group winner before losing, that set is suddenly worth an enormous amount. If they went down in straight sets twice, it probably does not matter how well they played the match they won.

If the sets percentage still leaves two of them identical — and it does, because these are small numbers and small samples — then games. Every game, in every match. A set won 6-0 is doing different work from a set won 7-6, and a player who lost 7-6, 7-6 has a better evening behind them than a player who lost 6-4, 6-2 even though both of them lost in straight sets.

It helps to put numbers on it. Suppose, hypothetically, that three players end a group on one win each. The first won her match 6-2, 6-2 and lost her other two 4-6, 2-6 and 6-7, 3-6. The second won 7-6, 6-7, 7-5 and lost twice in straight sets. The third won in three sets and lost one match in three and one in two.

On wins, all three are identical. On sets, the player who won two matches in straight sets and lost one in three is suddenly ahead of the player who ground out a three-setter, because grinding costs you a set. And if two of them come out of that level as well, the games column decides it, and the player who lost 6-7, 3-6 has quietly banked more than the player who lost 2-6, 2-6 on the same afternoon.

Which is why you will see a player, two sets down and plainly beaten, still chasing a ball into the corner at 1-5. They are not refusing to accept it. They are protecting a number that might be worth a semifinal in three days.

There is a wrinkle in the small print that a lot of fans never notice. Games won or lost in a match against a player who retired or was defaulted do not count towards the percentage at all. The rule exists so that a mid-match withdrawal cannot hand one person in a group an artificial pile of games, but it means the maths can quietly change shape halfway through a week if somebody pulls out.

And there is a separate rule again for the specific case where all three tied players have exactly one win: a player who has not completed all three of their matches is eliminated automatically, and the place goes to whoever won the meeting between the other two.

None of this is designed to be followed live. It is designed to produce a defensible answer. But it does create one of the oddest atmospheres in tennis: an arena full of people with phones out, doing division.

Dead rubbers, and matches that matter to somebody else

The other thing round robin invents is the dead rubber. A player can arrive for their third group match already through, or already out, with nothing whatsoever at stake for them.

Except it is almost never truly dead, because the scoreline still feeds somebody else's percentage. A player with nothing to play for is, at that moment, holding another player's season in their hands. Every November there is at least one match where the person on court has no reason to care and the person watching from the locker room has every reason in the world.

Crowds work this out quickly, and the noise in those matches is strange — much louder than the stakes on court would suggest, because half the building is cheering for a scoreline rather than a player. If you are following along at home across both weeks, the schedule is worth planning around; we laid out how to watch the November tennis month in one place.

The champions who lost on the way

Now for the part that makes the whole apparatus worth it.

In 2015, in Singapore, Agnieszka Radwanska lost two of her three group matches. By any normal reading of a tennis tournament she was finished. She scraped through anyway, and then beat Simona Halep, Garbine Muguruza and finally Petra Kvitova in the final, 6-2, 4-6, 6-3. She became the first player to win the WTA Finals after a 1-2 record in the group stage, and the first Polish winner of the event. Both finalists that year had lost two group matches, which had never happened before.

A year later Dominika Cibulkova did something arguably madder. She lost her opening group match to the world number one Angelique Kerber. Then she lost her second, to Madison Keys. Two matches into her tournament, with a 0-2 record, she was still alive only because the maths had not finished. She beat Halep in her final group match to reach 1-2, got through, and beat Kerber 6-3, 6-4 in the final.

In 2019 Ashleigh Barty lost to Kiki Bertens in the group, then beat Karolina Pliskova in the semifinal and the defending champion Elina Svitolina 6-4, 6-3 in the final.

The men have their version. In 2018 Alexander Zverev lost to Novak Djokovic in the group stage, found him again in the final, and beat him.

But here the two tours diverge in a way that says something about both. On the women's side, two players have won the title after losing two of their three group matches. On the men's side, in the entire history of the event, nobody has ever won it after losing more than one. Jannik Sinner won the last two without dropping a set at all.

Whether that is a difference in depth, in format history, in surface, or simply in sample size is the kind of argument tennis people enjoy having at midnight. What it means practically is that a 1-2 record at the WTA Finals is a real second life, and at the ATP Finals it is a statistical curiosity waiting for someone to end it.

Watching it properly

If you want to enjoy these two weeks rather than be confused by them, three habits help.

Watch the first set of every group match as though it were its own event, because it frequently is. Sets percentage has decided more semifinal places than most fans realise, and the difference between losing 6-3, 6-4 and losing 7-6, 6-4 can be a flight home.

Keep half an eye on the group table rather than the match. Tennis is not built for tables — there is no league in the sport, and the broadcast graphics often treat them as an afterthought — but for these two weeks the table is the story, and the match in front of you is a line in it.

And do not assume a handshake means goodbye. That is the single biggest adjustment for anyone used to normal tennis. A player can lose badly on Monday, look utterly beaten, and be lifting the trophy on Sunday. Radwanska did it. Cibulkova did it from a worse position. The format allows for a bad day in a way the rest of the season never does, and that permission changes how players behave — you see more risk, more willingness to go for a shot at 4-5, because the consequence of being wrong is smaller.

It is, when you step back from the arithmetic, an unusually humane piece of tournament design. The sport spends all year insisting that a single afternoon can define you. For a fortnight in November it says something gentler: show us three times, and we will take the balance of the evidence.

If the percentages come out and the arena goes quiet while eight thousand people do long division, that is not the format failing. That is the format doing exactly what it was built to do — refusing to let one bad hour be the whole answer. If you are still getting your bearings with the basics underneath all this, our guide to how tennis scoring works covers the ground the percentages are built on, and you can read the full preview of the week in the desert in our WTA Finals guide.

Sunday, Indian Wells, Rybakina against Noskova. Bring a calculator.

Photo: an overhead view of a hard court mid-rally, from our picture library.