The new site for the Miami Open suddenly is missing a lot of star power. Serena Williams withdrew Saturday, blaming a previously undisclosed left knee injury. Less than two hours later, top-ranked Naomi Osaka lost in the third round to tour veteran Hsieh Su-Wei of Taiwan, 4-6, 7-6 (4), 6-3. Osaka's departure matched the earliest ever in the tournament by a top-seeded woman and jeopardized her No. 1 ranking, depending on results next week.
"I feel like I've dealt with the stress of people asking me do I have pressure because I have the No. 1 next to my name," Osaka said. "I thought I was doing fine with that, but I guess I'm not."
Roger Federer briefly seemed headed for the exit but instead advanced to the third round by rallying past qualifier Radu Albot 4-6, 7-5, 6-3.
No. 2-seeded Alexander Zverev double-faulted 12 times and lost to wild card David Ferrer, 2-6, 7-5, 6-3.
Williams' withdrawal was unexpected because she showed no signs of injury a day earlier while winning her opening match against Rebecca Peterson, 6-3, 1-6, 6-1. Williams didn't mention any health issues during a news conference after the match, and the WTA had no information regarding when she was hurt. Williams' victory Friday was her first at Hard Rock Stadium, the Miami Dolphins' home and the Miami Open's new center court. The tournament moved this year from Key Biscayne, where Williams won eight titles.
"I am disappointed to withdraw," she said in a statement. Williams was next scheduled to play No. 18-seeded Qiang Wang, who advanced to the fourth round. Federer, a three-time champion, lost serve only once — in the first game — but was on the ropes until he swept the final three games, to the relief of an enthusiastic stadium crowd. Also reaching the women's round of 16 was the 33-year-old Hsieh, who turned pro in 2001 but has achieved the two biggest victories of her career in the past nine months. Her only other win over a No. 1 player came against Simona Halep at Wimbledon last year. When Hsieh closed out match point with a forehand volley winner, she began to cry as the crowd applauded her performance. Osaka smiled when reminded it was the first time in 64 matches she lost after winning the first set. Osaka, 21, has won the past two Grand Slam tournaments. Williams, 37, still hasn't won a tournament since the 2017 Australian Open, before she took a break of more than a year to become a mom.