Serena Williams has been forced to withdraw from the Miami Open due to a knee injury.
Williams, who won the most recent of her eight titles at the tournament in 2015, recorded a hard-fought victory over Sweden’s Rebecca Peterson in her opening game.
Two weeks ago, the 23-time grand slam champion retired from her third-round Indian Wells match against Garbine Muguruza citing “extreme dizziness and extreme fatigue,” which tournament organizers later identified as a virus.
“I am disappointed to withdraw from the Miami Open due to a left knee injury,” said Williams.
“It was an amazing experience to play at the Hard Rock Stadium this year and would like to thank the Miami Open for putting on an amazing event.
“I hope to be back next year to play at this one-of-a-kind tournament in front of the incredible fans here in Miami.”
Williams, whose last title came at the Australian Open in 2017, was scheduled to face China’s Wang Qiang on Monday.
Recently-crowned world No. 1 Naomi Osaka suffered a surprise defeat to Taiwan’s Su-Wei Hsieh, going down 4-6 7-6 (9-7) 6-3. Osaka split from her coach Sascha Bajin last month just 16 days after winning her second consecutive grand slam title at the Australian Open.
Petra Kvitova, who lost to Osaka in that Melbourne final, progressed in Miami after defeating Donna Vekic in three sets, 6-4 3-6 6-4.
In the men’s draw, Roger Federer and Novak Djokovic recorded opening victories against Radu Albot and Bernard Tomic respectively, but the tournament’s second seed Alexander Zverev was knocked out by Spain’s David Ferrer.