Cincinnati (AFP) - Rafael Nadal and Karolina Pliskova, the No. 1 seeds at the WTA and ATP Cincinnati Masters, never got a chance to break a sweat before play was halted on Thursday at the rain-hit tournament.
Czech defending champion Pliskova led Italian qualifier Camila Giorgi 3-0 when play was suspended, while former and future world No. 1 Nadal and compatriot Albert Ramos-Vinolas never started their third-round matches before the final drenching began.
Court conditions more suitable for Olympic swim star Michael Phelps than tennis stars had American 14th seed John Isner, who beat compatriot Frances Tiafoe 7-6 (7-4), 7-5, happy that he snuck in a win between the storms.
"Very happy to be off the court," he said. "We could have easily, if I didn't break at 5-all, we could be 2-all in a tiebreaker right now, not finishing. That would suck."
Second-ranked Simona Halep of Romania charged closer to taking the world No. 1 ranking from Pliskova by beating Latvian 15th seed Anastasija Sevastova 6-4, 6-3 to reach the quarter-finals.
"I'm not playing my best tennis in this moment, but I'm still winning," Halep said. "I win against the 15th player in the world, playing not like I want and I'm really happy about it."
But five matches were pushed to Friday, when double duty could come for Nadal, with the 15-time Grand Slam champion confirmed to return to the world No. 1 ranking next week.
Nadal was assured of advancing past the injured Andy Murray for the top spot when Roger Federer withdrew from Cincinnati with a back injury.
The 31-year-old Spaniard could meet Australian Nick Kyrgios in Friday's quarter-finals.
Croatia's Ivo Karlovic led Kyrgios 4-3 in their halted match.
Eighth-ranked Austrian Dominic Thiem, the only other seed remaining in Nadal's half of the draw, edged France's Adrian Mannarino 7-6 (7-4), 7-6 (7-3). He faces Spaniard David Ferrer in the quarter-finals.
Halep, a French Open runner-up for the second time in June, can overtake Pliskova by winning the title in the final Major tune-up for the US Open.
"To be No. 1 in the world I think is a big thing," Halep said. "If I deserve the place, for sure I will win it."
Ukraine's fourth-ranked Elina Svitolina, who won her fifth WTA title of the year last week in Toronto to reach a career-high fourth in the rankings, can also become No. 1 on Monday if she wins the title.
But she must face Germany's Julia Goerges in a postponed match, and then play the winner of another postponed match between American Sloane Stephens and Russian Ekaterina Makarova in a Friday double on short rest.
British seventh seed Johanna Konta downed Slovakian 11th seed Dominika Cibulkova 6-3, 6-4, to move into the quarter-final path of Halep, who won her 15th career WTA title earlier this year at Madrid.
Also reaching the quarter-finals was Wimbledon champion Garbine Muguruza.
The sixth-ranked Spaniard saved three match points in downing 17th-ranked American Madison Keys 6-4, 3-6, 7-6 (7-3).
"You never knew who was going to win until the last point," Muguruza said. "I had match points against me so it was really hard. I battled back and I'm glad things went my way."
Muguruza has a last-eight date with eighth seed Svetlana Kuznetsova.
The 32-year-old Russian, a two-time Grand Slam champion, eliminated Spain's Carla Suarez Navarro 6-2, 6-4.