Before each day of play at Roland Garros, we'll preview and predict three must-see matches.

Sharapova's last must-see showdown, against Sam Stosur in the third round, turned out to be a world-class dud. Could this one make up for it? Possibly. Maria is 4-1 against Safarova, but their last three matches, all of them won by the Russian, have gone the distance. In fact, their last meeting, on clay in Stuttgart in 2014, was a three-tiebreaker throwdown. Neither woman has dropped a set so far in Paris. Safarova, who got hot enough to reach the semis at Wimbledon last year, is capable of the upset, but Sharapova, who hasn’t lost before the semis in Paris since 2010, is the percentage pick. Winner: Sharapova

Now that Stephens is no long the “Next Serena” in the eyes of the media, can she beat Serena? If she does, she would become one of the few players to knock off both of the Williams sisters in the same event. The U.S. spotlight has shifted over to Madison Keys this year, and, for this tournament at least, that seems to have helped Sloane play calmer, more purposeful tennis. But as comfortable as she is at Roland Garros, where she has reached the fourth round for the fourth straight year, this match will still rest on her opponent’s racquet. The question for Serena is whether the challenge that she received from Victoria Azarenka in the last round, and the way she answered that challenge, will shift her into a higher gear for the rest of the event. It wouldn’t be the first time. Winner: S. Williams

One thing we know about this one: The ball is going to rotate. A lot. These two guys turn the ball over more times per millisecond than anyone else in tennis. But is that all we’re going to get from the 22-year-old Sock against the King of Clay? I don’t think so. I’m guessing he’ll put enough pressure on Rafa with his forehand to take a set. But while he’ll get his looks when Nadal leaves the ball short, it’s still not a great match-up for the American. He loves to run around his much more pedestrian backhand, and isn't afraid to backpedal all the way into the opposite alley to avoid it. But even that may not be far enough against Nadal’s lefty forehand spin. Sock has matured and improved this season, and even, seemingly, over the last week. But becoming the second man to beat Rafa at Roland Garros is probably a step too far for now. Winner: Nadal

It will be two-out-of-three sets when the Maestro and La Monf resume their fourth-rounder, second up on Chatrier. While Monfils won their last match in that format, in Monte Carlo in April, I think this helps Federer—the Frenchman is a notorious slow starter, and the 33-year-old Swiss won’t have to run around for four hours to win. But I’ll still take the home team in a close one. Winner: Monfils

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