Pliskova wins twice to reach semi-final

The tournament's top seeds then had only a few hours to eat, rest and prepare for quarterfinals matches.

Having served out for the set, Halep again quickly had the upper hand in the second with Stephens lacking precision on her groundstrokes.

Wimbledon champion Garbine Muguruza saved three match points on her way to beating American Madison Keys for the first time in four meetings. After a quick turnaround, she needed only 67 minutes to beat a rested Caroline Wozniacki 6-2, 6-4 for a sweep into the semis.

Meanwhile Halep, the world No 2, had not dropped a set in her opening two matches, making the quarter-final clash highly anticipated.

The third set was tied 2-2 when the first storm moved through the area in the afternoon, causing a almost two-hour delay. I fought so hard.

Muguruza grew up near Barcelona and learned about the attack in the Las Ramblas district during the rain delay. Her run ensures she will return to the top-100 in Monday's world rankings.

"I want to win it", Halep said. I thought he played a high-level match. I felt pretty good out there - under control.

Second-seeded Simona Halep became the tournament's first quarterfinalist with a 6-4, 6-3 win over 15th-seeded Anastasija Sevastova. "I m not playing my best tennis in this moment but I m still winning".

"To be No. 1 after all the things I've been going through the last couple years is something unbelievable", Nadal said.

Defending champion Karolina Pliskova won twice in one day for the third time this season, tightening her grip on the world number one ranking late on Friday to reach the WTA and ATP Cincinnati Masters semi-finals. Serena Williams from 2014 and 2015 remains the only back-to-back Cincinnati women's victor. The Spaniard had lost six straight matches against Pliskova since winning their first in 2013. The latter player amassed 11 winners, won 91 percent of her second serve points and converted five break points to move on. The 22-year-old from Canberra was up a double break in 10 minutes, seizing the chance to make a between-the-legs show off shot on his way to a 4-0 lead, drawing boos from the crowd. "I have no pressure", Halep said. "I went in the locker room, showered, changed, stretched, ate a little". "I think we both played very well, especially in the third set".

Stephens, playing just her fourth event after returning from a year-long hiatus due to a foot injury and related surgery, seemed to lack energy after reaching semifinals at back-to-back events at Toronto and Cincinnati.