Serena Williams's first tournament since the Australian Open came to an abrupt end on Sunday as the ailing 23-time Grand Slam champion retired from her third-round WTA match against Garbine Muguruza at Indian Wells.

Muguruza was leading 6-3, 1-0 when Williams called it a day in the battle of former World No. 1's because of a viral illness. "Before the match, I did not feel great, and then it just got worse with every second; extreme dizziness and extreme fatigue," Williams said in comments released via tournament organisers.