After an impressive opener, Jack Sock faces Tommy Haas in the second round at Roland Garros. (Michael Euler/AP)
Here are the storylines and matches to watch on Day 5 of the French Open. Play begins at 5 a.m. ET. Click here for the order of play.
Rain expected...again: Look for more matches to get cancelled and backed up to Friday. The forecast calls for a 60 percent chance of rain when play begins and rising to 80 percent in the evening. At a minimum, the last matches on each court will be under threat of cancellation, including Jack Sock vs. Tommy Haas, Ryan Harrison vs. John Isner, and others involving Richard Gasquet, Marion Bartoli, and Francesca Schiavone. Maria Sharapova, who takes on Canada's Eugenie Bouchard, and Rafael Nadal could also get bumped.
We're just one round away from...: A number of highly-anticipated third round matches are in the cards if only the key players can hold up their end of the bargain and win on Thursday. Novak Djokovic and Grigor Dimitrov are on a collision course, but Djokovic must first beat Guido Pella (second match, Court Philippe Chatrier) and Dimitrov has French wildcard Lucas Pouille (first match, Court Suzanne Lenglen). Samantha Stosur and Jelena Jankovic are also a win away from an intriguing match, and both will have to beat two talented youngsters. Stosur is under more threat against 20-year old Kristina Mladenovic (first match, Court Philippe Chatrier), who has quietly racked up some good wins to break into the top 50. Jankovic takes on Spain's Garbine Muguruza. And in one match that seems destined by the tennis gods, Nadal could face the last man to beat him at a Slam, Lukas Rosol. For that to happen, Rosol has to pull off the upset over 27th-seed Fabio Fognini.
Three (almost) All-American derbies: On one hand, it's never ideal for two Americans to have to play each other early at a tournament. On the other hand, at least it assures one will progress. Ryan Harrison will try and topple 19th-seeded John Isner for the second time this year, having beaten him in January in Sydney (fourth match, Court 3). Sloane Stephens is trying to advance to the third round of the fifth-straight Slam, taking on Vania King. And in the undercard of the day, 20-year old Jack Sock tries to upend 12th-seeded Tommy Haas (fourth match, Court 2). Haas has an American passport by virtue of his wife, actress Sara Foster. What? I said almost.
Matches to Watch
Tommy Haas vs. Jack Sock (fourth match, Court 2): Sock's straight set win over Guillermo Garcia-Lopez in the first round was impressive but Haas is, obviously, a completely different caliber player. His one-handed backhand can create angles that will get the young American on the run. Haas' willingness to finish points at the net will also keep the pressure on Sock to nail his passing shots. All that said, it must be said that Haas withdrew from last week's tournament in Dusseldorf due to illness and his wife says he played his opening round match "sick as a dog" and full of antibiotics. Sock's power game gives him a chance on any given day.
Li Na vs. Bethanie Mattek-Sands (first match, Court 1): The two played in the semifinals of Stuttgart, when Li put an end on what had been an incredible run for Mattek-Sands, beating the exhausted American 6-3, 6-4. That week, Mattek-Sands worked her way through qualifying and beat Sara Errani and Sabine Lisicki to earn her best career result. This time she comes in well-rested and could be primed to pull off the upset.
Ryan Harrison vs. John Isner (fourth match, Court 3): Harrison's biggest career win came at Isner's expense earlier in the year, when the younger American knocked an injured Isner out of Sydney 6-4, 6-4. The loss put Isner on a plane back to the States after he was forced to skip the Australian Open due to a knee injury. Both men have struggled this year but their first round wins were big confidence boosters and they come into this match with a lot on the line. Harrison has still never made the third round of a Slam while Isner hasn't made the third round of the French since 2010.
Sam Stosur vs. Kristina Mladenovic (first match, Court Philippe Chatrier): If I had to pick an upset of the day it would be this one. Mladenovic hits flat and takes the ball early, two things that can bother Stosur. The Aussie needs time to get set for her forehand and dictate and if Mladenovic is firing (that's a big if) she could pull it off. If she can get the home crowd into it, all the better.
Fernando Verdasco vs. Janko Tipsarevic (third match, Court 1)