American tennis star Serena Williams has withdrawn from the Miami Open with a left knee injury.
The Miami tournament is the second consecutive WTA event in which Williams has been unable to continue, after her retirement from last week's Indian Wells event with illness.
"I hope to be back next year to play at this one-of-a-kind tournament in front of the incredible fans here," the 36-year-old said.
The former world number one, an eight-time Miami Open winner, showed no signs of injury while winning her opener against Swede Rebecca Peterson 6-3 1-6 6-1.
Meanwhile, Miami-raised Japanese world number one Naomi Osaka was sent spinning to a crushing loss when unorthodox Taiwanese 27th seeded Hsieh Su-wei defeated her in three absorbing sets, 4-6 7-6(4) 6-3.
"This was a very emotional win for me," said Hsieh, who will now face either Caroline Wozniacki or Monica Niculescu in the fourth round.
"Any time you beat one of the top players it is amazing."
Elsewhere, world number two Petra Kvitova was extended to three sets before the Czech overcame Croatia's Donna Vekic in the third round.
Two-time Wimbledon champion Kvitova finally prevailed 6-4 3-6 6-4 in the clash between two heavy hitters, requiring more than two-and-a-half hours. Kvitova, the third seed, will next meet France's Caroline Garcia.
Garcia had earlier knocked out 15th seed Julia Goerges, of Germany, 6-0 7-5.
Ashleigh Barty has progressed to the fourth of the Miami Open after winning her All-Australian showdown against Samantha Stosur in straight sets.
In the second career meeting between the two players, it was the nation's top- ranked player who came out on top against former US Open champion Stosur, earning a comprehensive 6-0 6-3 win in 58 minutes.