Simona Halep's first win in three months highlighted the second day of the Western and Southern Open.
The former world No. 1 won a three-set battle with Magda Linette in one of the first completed matches of the day.
For the second straight day, rain delayed play in Ohio. Some of the matches lasted deep into the night and will force a short turnaround for some players going into the next rounds.
Sloane Stephens and Caroline Garcia were the last two players on court. Garcia bested Stephens in a three-set match that ended around 2 a.m. ET.
Matteo Berrettini finished his match with Albert Ramos-Vinolas at a fairly reasonable time, but it took longer than expected for him to advance into the third round.
The Wimbledon runner-up holds a rare advantage over the rest of the men's singles field since he was the first player to clinch his spot in the third round. The first round was completed late Tuesday night.
Wednesday's action will begin at 10 a.m. ET and six matches are scheduled to be played on Center Court. The full order of play can be found here.
No. 5 Matteo Berrettini def. Albert Ramos-Vinolas, 6-7 (5), 6-3, 7-5
Benoit Paire def. No. 6 Denis Shapovalov, 6-3, 4-6, 7-5
No. 9 Hubert Hurkacz def. Alejandro Davidovich Fokina, 6-1, 6-7 (3), 6-1
Grigor Dimitrov def. No. 13 Roberto Bautista Agut, 6-3, 6-4
Tommy Paul def. No. 16 Cristian Garin
Gael Monfils def. Dusan Lajovic, 7-6 (0), 6-2
Alexander Bublik def. Marcos Giron, 3-6, 6-3, 7-6 (5)
Marin Cilic def. Aslan Karatsev, 7-5, 6-3
John Isner def. Cameron Norrie, 4-6, 7-6 (5), 6-4
Sebastian Korda def. Laslo Djere, 6-4, 6-4
Reilly Opelka def. Corentin Moutet, 7-6 (3), 4-6, 6-4
Lorenzo Sonego def. Carlos Alcaraz, 6-3, 7-6 (6)
Frances Tiafoe def. Ugo Humbert, 7-5, 7-6 (9)
Berrettini needed an extra set to eliminate Ramos-Vinolas, but he is now in an ideal situation to make a deep run.
The No. 5 seed was able to complete his second-round match during a hectic night session in which first-round matches were finished up because of the delays from Monday and Tuesday.
Berrettini will have a rare day to recover. Most players are on court every day for one-week events, especially in the latter rounds.
The Italian hit 25 aces in his first match since losing the Wimbledon final to Novak Djokovic. He was pushed to a 12-game third set by Ramos-Vinolas but eventually pulled out the victory.
Roberto Bautista Agut was not as lucky as Berrettini on Tuesday. He became the second of the 16 men's seeds to lose. He was dropped in straight sets by Grigor Dimitrov. Denis Shapovalov and Cristian Garin were also knocked out at end of Tuesday's action.
If Dimitrov plays at the same level he did on Tuesday, he could give No. 1 seed Daniil Medvedev a bit of a challenge in their potential third-round showdown.
The bottom part of Dimitrov's section contains one of the most intriguing second-round matchups, as No. 9 seed Hubert Hurkacz faces Andy Murray.
The Polish player continued his strong season with a three-set victory in which he won two sets by a 6-1 margin.
The crowd will likely be on Murray's side during their head-to-head showdown, but the two men have never faced each other before on the ATP Tour.
A slew of unseeded Americans moved into the next round as well. Sebastian Korda, John Isner, Frances Tiafoe and National Bank Open finalist Reilly Opelka will all face seeded players in the second round.
No. 10 Belinda Bencic def. Marketa Vondrousova, 6-3, 7-5
No. 12 Simona Halep def. Magda Linette, 6-4, 3-6, 6-1
No. 14 Victoria Azarenka def. Liudmila Samsonova, 6-2, 6-3
Jessica Pegula def. Camila Giorgi, 6-2, 6-2
Veronika Kudermetova def. Jasmine Paolini, 6-3, 6-2
Coco Gauff def. Hsieh Su-Wei, 6-1, 6-2
Elena Rybakina def. Samantha Stosur, 6-3, 6-3
Bernarda Pera def. Rebecca Peterson, 6-4, 6-1
Karolina Muchova def. Johanna Konta, 3-6, 7-6 (7-5), 6-2
Ons Jabeur def. Anett Kontaveit, 6-2, 4-6, 7-5
Halep earned her first victory during her return to the court with a solid performance over three sets.
The Romanian was sidelined by a calf muscle tear and did not play at the French Open or Wimbledon.
Halep lost in her opening match of the National Bank Open last week to Danielle Collins. She will play another American, Jessica Pegula, in the second round of the Western and Southern Open.
The No. 12 seed opened with a first-set victory, but Linette battled back to take the middle set. Halep slammed the door on her opponent in the final set by conceding a single game.
If Halep wins her second-round match, she will face a gauntlet of fellow seeds just to get out of her section. Karolina Pliskova, Elise Mertens and Aryna Sabalenka were drawn into that portion of the bracket.
Halep was one of three seeded women to move on to the next round on Tuesday. Belinda Bencic and Victoria Azarenka both won in straight sets under the lights.
Halep's next opponent is one of six American women remaining in the draw. Stephens could not make that total seven, though. She fell in three sets to Garcia in the final match of the night.
Garcia won a battle in the first set. She needed two extra points in the tiebreak to take the early edge on Stephens.
To her credit, Stephens battled back to win the second set, but she was unable to complete the comeback. Garcia earned a key service break in the third set to go ahead for good.
All 15 women's singles seeds who entered the draw are still in the tournament. Anastasia Pavlyuchenkova was seeded 16th, but she was forced to withdraw due to visa issues.
No. 1 seed Ashleigh Barty, Elina Svitolina and Bianca Andreescu are among the seeded women set to take the court for the first time in Ohio on Wednesday.