10 Things to Know, Day 5: Only one woman can take No. 1 from Osaka now

Trivia: Dominic Thiem is going for his 50th career match win at a major today, which would make him the third Austrian man to reach that milestone. Who were the first two? Check back tomorrow for the answer.

The second round wraps up today

It is a packed schedule on Thursday, highlighted by world No. 1s Naomi Osaka and Novak Djokovic playing back-to-back from 11 a.m. on Lenglen, and Serena Williams playing on Chatrier.

Only one woman can take No. 1 from Osaka now: Karolina Pliskova

Pliskova needs to reach the final (with Osaka losing before the semifinals) or win the title (with Osaka losing before the final) to take No. 1.

Osaka was two points from losing her first round match

Anna Karolina Schmiedlova served for the match twice at 6-0, 5-4 and 6-0, 6-5—she was also two points away five times in that 6-5 game. But Osaka fought back to win, 0-6, 7-6 (4), 6-1, her first time coming back from a 0-6 first set to win a tour-level match.

Osaka’s opponent today, Victoria Azarenka, has beaten No. 1s before

Azarenka, a former No. 1 herself, has three career wins over No. 1s, all over Serena and all in finals—at Miami in 2009, Cincinnati in 2013 and Indian Wells in 2016. She has never beaten a No. 1—or even a No. 2—at a major, though.

Djokovic plays a lucky loser—he has never lost to one at tour-level

The Serb is 9-0 in his career against lucky losers in tour-level matches. He plays Swiss lucky loser Henri Laaksonen today.

Unlike Osaka, Djokovic’s No. 1 ranking is 100% safe here

But No. 2 is up for grabs—whoever does better between Nadal and Federer will be No. 2, and if they lose in the same round, Federer will take it.

Serena is 67-2 in second round matches at majors

Her only losses in this round came to Venus at the 1998 Australian Open—the first major she ever played—and Muguruza at the 2014 French Open.

Serena has only won a Slam once after losing her first set of the tournament

Serena beat Vitalia Diatchenko in the first round, 2-6, 6-1, 6-0. The only time she has won a major after losing her first set of the tournament was at the 2003 Australian Open—she beat Emilie Loit in the first round, 3-6, 7-6 (5), 7-5.

More than half of Thiem’s career match wins have come on clay

Of his 243 tour-level match wins, 125 have come on clay; meanwhile, 104 have come on hard courts and just 14 on grass.

Monfils has never lost to another Frenchman at the French Open

He is 5-0 against countrymen at Roland Garros; meanwhile, he is 10-6 against countrymen at the other three majors combined.

Trivia Answer from yesterday: This is the 800th straight week that one of the Big 4 is No. 1, and No. 1 on the ATP rankings 801 weeks ago—right before this streak began on February 2, 2004—was Andy Roddick.