- Williams appeared to roll her right ankle late in the first set
- She received treatment for the injury, as well as for a knee complaint, before deciding to continue
- The American saved three match points before going down to Errani
Williams was troubled by ankle and knee injuries but chose not to retire, before going down 6-1, 6-0 to Errani on John Cain Arena.
The 40-year-old’s decision to play on was admired by the small crowd attending the match, who enthusiastically cheered every point she won when she was clearly in pain.
Williams appeared to roll her right ankle as she approached the net during a rally with Errani, who was leading 5-1 in the first set at the time.
The American seven-time major singles winner was allowed a medical timeout to receive treatment for the injury, with the two trainers applying strapping to her right ankle.
She was immediately given a second medical timeout to receive treatment on an existing left knee complaint before returning to the court.
It was clear Williams was experiencing significant discomfort. Her movement was restricted and she was limping between points, while the disconsolate look on her face illustrated her flagging spirits.
After Errani quickly wrapped up the first set, Williams chose to play on.
Trailing 0-2, she impressively claimed three break points in the third game through some powerful hitting from the baseline, but the Italian responded and eventually held serve.
While Williams, twice a singles finalist at Melbourne, was able to hit her groundstrokes with some of her trademark ferocity, she was forced to serve at a much slower speed than normal.
She looked like she might hold serve in the fourth game of the second set, however Errani broke to extend her lead.
When serving to stay in the match at 0-5, Williams refused to give up and was a point away from holding when she was 40-30.
Errani fought back and twice had match points, but both were saved by Williams with blistering forehands.
Williams could not save a third match point, however, and Errani completed her victory after an hour and 15 minutes on court.
Williams had advanced to the second round after beating Kirsten Flipkens on Monday.
Younger sister Serena, a seven-time Australian Open winner, won through to the third round earlier on Wednesday following a 6-3, 6-0 victory over Nina Stojanović.