Tuesday Madrid Previews: Kerber vs. Martic; Thiem vs. Opelka

UPDATE: Angelique Kerber has withdrawn from her second-round match with ankle injury.

Angelique Kerber (WTA No. 4, UTR No. 10) vs. Petra Martic (WTA No. 36, UTR No. 24)

At first glance, this might not look like one of Tuesday's most exciting matchups. But when you dig deeper, this match has some serious upset potential.

Kerber is in decent form at the moment, having made a run to the Indian Wells final to go along with a handful of quarterfinals and semifinals, but she has yet to win a title in 2019. Now, she is playing on clay, statistically her worst surface. At the same time, her Croatian opponent is currently playing the best tennis of her life, on her favorite surface. Martic made the semifinals in Charleston, then won her first career title last week in Istanbul. In Madrid, she's already taken out Garbine Muguruza in straight sets.

Martic has a perfect game for clay, with movement and athleticism her biggest strengths, in addition to a very effective kick serve. She plays high and heavy but also mixes in a backhand slice to change up pace. She will try to control the point with her serve and forehand to keep the ball out of Kerber’s strike zone. Kerber will use her picture-perfect groundstrokes to hit sharp angles and clean winners, like she always does.

Kerber should still win this match, but don’t be shocked if Martic walks away with the biggest win of her career over the world No. 4.

Reilly Opelka (ATP No. 58, UTR No. 66) vs. Dominic Thiem (ATP No. 5, UTR No. 7)

For young players, competing against the very best in the world is a tremendous opportunity to assess your game. After fighting through the qualifying and dispatching Spaniard Pablo Carreno Busta in the first round, Opelka will now get to measure up against perhaps the second-best clay court player in the world in Thiem.

If Opelka can do any sort of damage against Thiem on clay, it will be a moral victory. Thiem is a massive favorite, both according to the UTR metrics as well as the Vegas oddsmakers. All Opelka can try and do is hold serve efficiently and avoid any extended, physical rallies. While clay is not Opelka’s preferred surface, he can serve big enough to trouble Thiem—and anyone else, for that matter, on any surface.

Look for Thiem to take pace off of his first serve and stretch the seven-foot American out wide to start points, using his brutally heavy topspin to dictate every rally on his serve. This match is a win-win scenario for the American. Regardless of the result, he should relish the opportunity to measure his game against a truly great clay-court player.