Tennis: Halep battles in Miami fourth round, to face Venus

Simona Halep of Romania kept alive hopes of regaining the world number one ranking Sunday, beating Polona Hercog of Slovenia 5-7, 7-6 (7/1), 6-2 to reach the last 16 of the WTA and ATP Miami open.

The 27-year-old lost her place at the world top position in the women's game after losing to Japan's Naomi Osaka at the Australian open earlier this year.

But with the Japanese faltering on Saturday, Halep can return to the top position she last held at the end of 2018 if she lands the Miami open for the first time.

Simona Halep of Romania plays against Polona Hercog of Slovenia on Day 7 of the Miami open at Hard Rock Stadium in Miami Gardens, Florida, U.S., March 24, 2019. /VCG Photo

The Romanian, who will also move up the to the top of the rankings if she reaches the final and Petra Kvitova of Czech Republic doesn't win the title, will certainly have to put in a better display than the patchy performance which however still sent the gutsy Hercog, the world no. 93 from Slovenia, out.

"She played unbelievable and it was such a tough match," said Halep, who belted 48 winners compared to her opponent's 38.

"It was good to play for almost three hours though. I slowly found my rhythm but I always had belief so if I can keep doing this, I will have a good tournament.”

She next faces seven-time Grand Slam champion Venus Williams of the U.S., who swept past Russian Daria Kasatkina 6-3, 6-1.

Halep, the 2018 French open champion, and current world no. three, arrived in Miami having failed to get past the round of 16 in Indian Wells and the quarter-finals in Dubai.

Polona Hercog of Slovenia returns a shot against Simona Halep of Romania during Day 7 of the Miami open at Hard Rock Stadium in Miami Gardens, Florida, U.S., March 24, 2019. /VCG Photo

She started sluggishly on the center court at Hard Rock Stadium, where Hercog moved into an early 3-1 lead.

Halep finally broke back for 4-4 but another sloppy game handed Hercog the opportunity to grab a first set lead which she duly took.

Halep was far more solid in the second, despite missing the chance to draw level when she was broken serving at 5-3 and Hercog kept her nerve make it 5-5.

As the clock ticked past two hours, a brilliant drop shot by Hercog ensured a second set tie break only for Halep to emphatically win it 7-1 before the decider was sealed for the Romanian when she held to love after 2 hours and 50 minutes.

John Isner of the U.S. celebrates winning his match against Albert Ramos Vinolas of Spain during Day 7 of the Miami open at Hard Rock Stadium in Miami Gardens, Florida, U.S., March 24, 2019. /VCG Photo

On the men's side, defending champion John Isner of the U.S. blew Spain's Albert Ramos-Vinolas off the court as the American sealed an ultimately comprehensive 7-5, 7-6 (8-6) win.

He was broken in the very first game but responded by hitting a total of 16 aces to set up an intriguing match with Kyle Edmund in the last 16 after the British number one impressively saw off Canadian Milos Raonic 6-4 6-4.

"I did a lot of things well," Isner said. "I played a good first set, even though I didn't start it off well. In the second, it wasn't quite as clean. But I'm into the round of 16 of a big tournament and I'm happy."