The 2019 US Open started on Monday, and there was already drama on the courts. Several top seeds fell in early upsets, and both Ashleigh Barty and Karolína Plíšková, ranked at 2 and 3 respectively, struggled to beat their first round opponents on Monday.
Here’s a quick rundown of the happenings from the USTA Billie Jean King National Tennis Center.
Federer, Keys overcome slow starts
Both Roger Federer and Madison Keys stumbled early on Monday night — and looked like they could be on their way to a quick exit from the U.S. Open.
No. 10 seed Keys escaped a tight first set against Japan’s Misaki Doi 7-5, while No. 3 seed Federer fell to India’s Sumit Nagal 6-4 in his first set.
The early scares, though, seemed to be exactly what the pair needed.
Federer responded quickly, easily winning three-straight sets 6-1, 6-2, 6-4 to put Nagal away. Keys then dominated her second set 6-0 to take her opening round win.
Federer will advance to take on Bosni and Herzegovina’s Damir Dzumhur in the second round, and Keys will take on China’s Lin Zhu.
Serena Williams cruises past Maria Sharapova
Serena Williams had little issue getting out of the first round on Monday night.
No. 8 seed Williams cruised past Maria Sharapova 6-1, 6-1 in her first appearance back at the U.S. Open since her infamous meltdown in the championship match last year.
Williams will now advance to the second round, where she’ll take on American Catherine McNally on Wednesday.
No. 14 seed Angelique Kerber continues to have a rough 2019, as she lost to Kristina Mladenovic, who is ranked 54th. This exit comes after she lost in the second round of the French Open and Wimbledon earlier in the year.
Kerber dropped the first set, 7-5, before storming back and winning six straight games to capture the second set 6-0. It seemed like Kerber had overcome her stumble, but the third set was a battle. The two kept it close throughout, but Mladenovic ended up winning the set 6-4, and took the match.
Meanwhile on the men’s side, No. 11 seed Fabio Fognini dropped his match to American Reilly Opelka 6-3, 6-4, 6-7, 6-3. Opelka pulled away with 26 aces to Fognini's 18, earning him a striking 88 service points won over the four sets.
Novak Djokovic, Venus Williams wins in straight sets
The defending US Open champion Novak Djokovic made easy work of his first-round opponent, Roberto Carballés Baena, as he seeks his 17th Grand Slam Title. The 32-year-old won his match in just under two hours, 6-4, 6-1, 6-4.
Djokovic won a clean game in his first match against the Spain native and did not break a single set, only committing three double faults. Djokovic will face the winner of Sam Querrey and Juan Ignacio Londero in the next round, and he won't have to face a ranked opponent until potentially meeting No. 27 Dušan Lajović in the third round.
Williams handled 25-year-old Zheng Saisai in straight sets as well, 6-1, 6-0. Williams was nearly flawless, winning 81 percent of her first serves and winning 12 points in a row at one point. She will a tough draw in the second round, likely No. 5 Elina Svitolina.
Ashleigh Barty escapes with a close call
Barty was facing Kazakhstan’s Zarina Diyas, ranked 80th in the world, and early on it looked like Diyas would cruise to a win. Diyas won the first set 6-1, with Barty making a number of sloppy mistakes and generally not looking like herself. She rebounded in the second set, gaining confidence as she went along and eventually winning 6-3. Barty was completely herself in the third set, which she won 6-2.
Plíšková’s match against 212-ranked Tereza Martincova was more of a nailbiter. The two traded games throughout the first set, with Martincova coming within two points of securing the first set. Plíšková battled back and forced a tie-breaker, winning 7-6(6). The first set win led to her going up 3-0, but Martincova staged her own comeback. The game came down to another tie-breaker, and Plíšková managed to take it and win 7-6(3).
More from Yahoo Sports: