Mason - Madison Keys used her forehand to beat Angelique Kerber - one of her toughest matchups - and advance to the quarter-finals of the Western & Southern Open on Thursday between more bursts of rain.
Three matches held over from the previous night had to be completed first.
Top-ranked Simona Halep needed only eight points to complete a gritty comeback that was put on hold overnight by the rain, beating qualifier Ajla Tomljanovic in three sets and then getting some rest with another match scheduled for the night session.
After Halep left centre court, the 13th-ranked Keys steadied herself after a ragged first set. She'd lost five straight matches against No. 4 Kerber, but relied on her forehand to rally for a 2-6, 7-6 (3), 6-4 win. She hit 35 forehand winners, including the match-ending shot for her first Cincinnati quarter-finals.
Halep faced an unusual challenge because of the rain.
Fresh off her second Rogers Cup title, Halep arrived in Cincinnati looking to extend her momentum toward the US Open. She appeared to aggravate her lower back on a 105 mph serve during the second set on Wednesday night. After losing the first three games of the final set, she took a medical timeout for treatment.
Halep returned to the court and took control, running off four straight games for a 4-3 lead when rain arrived. Seventeen hours later, she was back on court and needed only 5 minutes to complete the 4-6, 6-3, 6-3 win on Thursday afternoon.
"I have learned that I don't have to give up, because anything can happen," she said.
Halep was scheduled to face Ashleigh Barty in the last match on Thursday night, with the winner advancing to the quarterfinals.
Two other second-round matches had to be completed.
Amanda Anisimova beat qualifier Petra Martic 6-4, 6-3 in a match suspended overnight. Fourth-seeded Juan Martin del Potro beat Hyeon Chung 6-2, 6-3, finally completing the second round in late afternoon. The winners faced the challenge of playing essentially two full matches in one day.
As the suspended matches wrapped up, the third round began on other courts in a tournament that had already lost top players.
No 2 Caroline Wozniacki retired from her match Wednesday night because of an injured left knee, her second straight disappointing exit from a tournament. Wozniacki lost her opening match last week in Montreal.
On the men's side, No 1 Rafael Nadal withdrew from the tournament after winning his fifth title of the year in Toronto, deciding it was best to get a little rest with the US Open approaching.
Roger Federer is the top-ranked player left in a tournament he's won a record seven times. He and Nadal have been locked in a back-and-forth atop the rankings, exchanging the No. 1 spot six times in the last six months. Nadal will be No 1 heading into the Open.
Novak Djokovic also made it to the third round, carrying the momentum from his Wimbledon title. Djokovic has never won a Western & Southern title, the only ATP Masters 1000 championship to elude him. He's reached the finals five times and lost every time. Djokovic is trying once again to become the first to win all nine ATP Masters events.
Results from the ATP and WTA Cincinnati Masters tournament on Thursday (x denotes seeding):
Juan Martin del Potro (ARG x4) bt Chung Hyeon (KOR) 6-2, 6-3
Milos Raonic (CAN) bt Denis Shapovalov (CAN) 7-6 (8/6), 6-4
Pablo Carreno-Busta (ESP x13) bt Robin Haase (NED) 6-4, 6-2
Simona Halep (ROM x1) bt Ajla Tomljanovic (AUS) 4-6, 6-3, 6-3
Amanda Anisimova (USA) bt Petra Martic (CRO) 6-4, 6-3
Lesia Tsurenko (UKR) bt Ekaterina Makarova (RUS) 7-6 (7/5), 6-2
Madison Keys (USA x13) bt Angelique Kerber (GER x4) 2-6, 7-6 (7/3), 6-4
Aryna Sabalenka (BLR) bt Caroline Garcia (FRA x6) 6-4, 3-6, 7-5
Petra Kvitova (CZE x8) bt Kristina Mladenovic (FRA) 6-4, 6-2
Elise Mertens (BEL x15) bt Sloane Stephens (USA x3) 7-6 (10/8), 6-2