Fresh concerns surrounded the fitness of Serena Williams at the Australian Open on Tuesday when she suffered a recurrence of her ankle injury while playing doubles.
Williams twisted her right ankle in the first round of the singles but the world number three had been untroubled while moving through to her quarter-final appointment with Sloane Stephens, to be played on Wednesday.
However, she tweaked the ankle again as she and her sister, Venus, were defeated by the top-seeded Italian duo of Sara Errani and Roberta Vinci on Tuesday. The 12th-seeded Americans were defeated 3-6, 7-6 (7/1), 7-5.
Williams, who served for the match in the second set, grimaced at various stages of the clash and her movement was restricted.
The world number three won singles titles at Wimbledon, the US Open, the London Olympics and the WTA Championships last year, and is eyeing the first calendar-year Grand Slam since 1988.
Errani and Vinci will next meet the number four seeds, the Russian pairing of Ekaterina Makarova and Elena Vesnina, for a place in the final.