Miami Open: Naomi Osaka reaches fourth round with walkover

March 28 (UPI) -- Tennis star Naomi Osaka advanced to the fourth round of the Miami Open on Sunday after her opponent, Nina Stojanovic, withdrew from their scheduled match due to a right thigh injury.

With the walkover, Osaka reached the fourth round at the Miami-based tournament for the first time in her career.

Osaka, who is ranked No. 2 in the world, has won 22 straight matches since her most recent loss in February 2020. She earned her fourth Grand Slam title at the Australian Open last month.

In the next round, Osaka will face No. 16 Elise Mertens, who defeated No. 22 Anett Kontaveit 6-2, 0-6, 6-2 to advance.

Also Sunday, fourth-seeded Sofia Kenin suffered a 6-4, 4-6, 6-4 loss to No. 27 Ons Jabeur. No. 29 Jessica Pegula also posted an upset victory with her 6-1, 4-6, 6-4 triumph over No. 6 Karolina Pliskova.

On the men's side of the Miami Open, top-ranked Daniil Medvedev beat Alexei Popyrin 7-6 (3), 6-7 (7), 6-4 in the third round Sunday.

Medvedev overcame severe cramps late in the match to earn the victory.

"I felt like my legs were not following me anymore," Medvedev said. "The only thing I was thinking about is not to fall down, because if you fall down, I don't think I would be able to get up.

"There were a few moments I just wanted to lay down and say, 'OK, it's over.' That's the thing I couldn't accept myself to do."

Also advancing was No. 18 John Isner, who is the only former Miami Open champion in the men's field. He edged No. 11 Felix Auger-Aliassime 7-6 (5), 7-6 (5) to reach the next round.

No. 7 Roberto Bautista Agut rallied past No. 31 Jan-Lennard Struff 4-6, 6-3, 6-2 to set up a fourth-round matchup against Isner.