Previews: Federer vs. Wawrinka leads French Open quarterfinal slate

Before each day's play at the 2019 French Open, we'll preview three must-see matches.

Anyone who makes the quarterfinals of a major is, by definition, playing well, but that goes double for Stephens and Konta right now. In the last round, Stephens bamboozled 2016 Roland Garros champ Garbiñe Muguruza, while Konta blitzed past Donna Vekic the same she has blitzed past her 9 of her last 10 opponents. The Brit might be on the most surprising run of good form of 2019. Never known as a clay-courter—she hadn’t won a match at the French Open before last week—Konta reached the Rome final and has now made herself a front-runner in Paris. She’s playing with total clarity at the moment. Can Stephens, a finalist here last year and a more natural dirt-baller, make Konta’s life complicated again? Konta beat her in three sets in Rome, but Stephens has always been a step-up player at the Slams. Winner: Stephens

Federer is 22-3 against Wawrinka. He has won their last six meetings, all but one of them in straight sets. He hasn’t dropped a set in his first four matches at Roland Garros. And while he cruised through his fourth-rounder on Sunday, his countryman was toiling in the heat for five hours against Stefanos Tsitsipas in the marathon match of the year. Is there any chance that Federer doesn’t win this? Wawrinka says he’ll be ready for a “big fight,” and the last time they played on Court Suzanne Lenglen, in 2015, he recorded his only win over Federer at a major, in three commanding sets. The surface should give Stan something of a chance; all three of his wins against Federer have come on clay. And it’s possible that his long hours on court against Tsitsipas were better preparation than Federer’s easy pickings through the first four rounds. Federer will have to adjust to a higher, fiercer level of play now. He probably will. Winner: Federer

The masses may leave after Federer-Wawrinka, but the tennis lovers will want to stick around for this display of finesse and subtle skill, even if they haven’t heard of the players. Vondrousova, 19, and Martic, 28, are both making their Grand Slam quarterfinal debuts, and the way they’re playing, they must feel as if they have a chance to go much farther. While Vondrousova is still in her teens, she has already faced Martic four times, and she has lost all four of those matches. But their most recent meeting, in the Istanbul final a month ago, was the first in which Vondrousova took a set (that was also was the only time they’ve met on clay). Since then, Vondrousova has only gotten better. While Martic has the bigger win in Paris, over No. 2 seed Karolina Pliskova, Vondrousova hasn’t been challenged at all. Winner: Vondrousova

Wawrinka and Nishikori are in similar boats: They have uphill climbs against legendary opponents, which have been made even steeper by the difficulty level of their fourth-round matches. Nishikori is 2-10 against Nadal, and 0-4 on clay—though he was leading Rafa in Madrid a few years ago before he hurt himself and had to retire. Now, after completing a five-set win over Benoit Paire on Monday, he’ll have to play Nadal without a rest day. It won’t help that Nishikori also won his third-round match in five sets. Kei has been clutch, but he may regret having to be. Winner: Nadal

Catch up on Week 1 at Roland Garros on the TENNIS.com Podcast: