This article is part of our What We Learned series.
The clay-court season is in full swing and both the ATP and WTA tours made a stop in Spain this past week. With the French Open looming later this month, here's what we learned at the Madrid Open.
Rafael Nadal looks somewhat vulnerable on clay
Nadal is 20-5 on the season, but he's yet to win a title, which is especially surprising considering he's played in three clay events. The 32-year-old Spaniard has fallen short against Fabio Fognini, Dominic Thiem and Stefanos Tsitsipas on clay to start the year. He'll still be the favorite for Roland Garros since he's won it 11 times and thrives in best-of-five tournaments, but he looks more vulnerable than normal this season on clay.
Naomi Osaka is losing grip on No. 1 ranking
Osaka fell in the quarterfinals of Madrid during a tough three-setter to Belinda Bencic. Since her Australian Open title, Osaka doesn't have anything better than one semifinal result across her five following tournaments this season. As a result, the 21-year-old from Japan is barely holding on to the No. 1 ranking in the world. Simona Halep nearly recaptured the top spot, but was unable to do so when she lost in the Madrid final. Osaka peaks for Grand Slam tournaments, which is admirable, but her consistency in smaller events is still questionable. That said, she will be a threat to win any tournament she enters, while keeping in mind that clay is not her best surface.
Stefanos Tsitsipas is the real deal
At just 20 years old, Tsitsipas already has wins over Roger Federer, Novak Djokovic and Rafael Nadal. The youngster from Greece ousted the King of Clay on his home soil in Madrid for his latest impressive win and now leads the tour with 27 wins. He's already firmly entrenched inside the top 10, and he's going to make a push for the top five while already at a career-high ranking of No. 7 after Madrid.
Sloane Stephens' 2019 slump is over
Stephens picked up her first semifinal result of the season in Madrid, which is a bit of a disappointment considering she's a top-10 player in the world. The 26-year-old American came into the Madrid Open with a record of just above .500, so this week was big for her to gain some confidence, especially with Roland Garros looming, where she was the runner-up in 2018.
Novak Djokovic is ready to push for second Roland Garros title
After Djokovic rolled to his third consecutive Grand Slam title at the Australian Open, he racked up losses to Roberto Bautista Agut, Philipp Kohlschreiber and Daniil Medvedev in his next three events. He rounded back into top form in Madrid, however, as he defeated the likes of Dominic Thiem and Stefanos Tsitsipas to win his second title of 2019 and the 33rd Masters 1000 victory of his career. The 31-year-old Serbian looks poised to make a run for his second title at Roland Garros, which would mark his fourth consecutive major title. His biggest rival for the title will certainly be Rafael Nadal, who has 11 Roland Garros titles, but hasn't been quite at his best yet this year.
Roger Federer won't be favored on clay
Federer played in his first clay-court event in three years, and saved match points in his third-round win over Gael Monfils, before wasting match points in a tight three-setter against Dominic Thiem in the quarterfinals. The 37-year-old from Switzerland will only be considered the fourth favorite at the French Open behind Rafael Nadal, Novak Djokovic and Dominic Thiem, but he'll still certainly be a threat to make a deep run at the event.
Simona Halep is close to reclaiming top spot
Halep could have reclaimed the No. 1 ranking with a title victory, but she fell just short, losing to Kiki Bertens for the second consecutive time. The 27-year-old Romanian looks to be nearing her best tennis as Roland Garros nears, which is ideal considering she is the defending champion. Halep is a great 23-7 on the season, but she doesn't have a title, which indicates that she has been consistently good while still being outplayed in the latter stages of tournaments.
Alexander Zverev is being overshadowed in 2019
Zverev, ranked No. 3, came in as the defending Madrid champion, but he remains without a title in 2019 after he lost to Stefanos Tsitsipas in the quarterfinals and dropped to 15-9 on the season. The 22-year-old German is off to a shaky start to the season despite winning the ATP World Tour Finals in London at the end of 2018. He is being overshadowed so far this season by the likes of other contenders like Dominic Thiem and Stefanos Tsitsipas, but it's likely only a matter of time until he turns his season around.
Kiki Bertens shouldn't be overlooked
The 27-year-old Dutchwoman capped off the biggest week of her career by staving off Simona Halep, who was gunning for the No. 1 ranking in the world, in the finals of Madrid. Bertens achieved a career-high ranking of No. 4 with the Madrid title, which she captured without losing a set, becoming the first woman to ever achieve that feat. Bertens has two titles on the year, and after defeating two top five players en route to this title, it's clear that she'll be a major threat at Roland Garros later this month as she seeks her first Grand Slam title.
Felix Auger-Aliassime looks more promising than Denis Shapovalov
At 18 years old, Auger-Aliassime has already made one tour final, something Shapovalov has yet to do. Auger-Aliassime also defeated Shapovalov 6-2, 7-6 (7) in Madrid before losing to Rafael Nadal. He's 17-10 on the season, and is already looking more consistent than the streakier Shapovalov.