She brushed off the practice-session interruption, saying, "You know, this week, the weeks leading up, have been a lot of work. I actually wanted to have an easy day today. But to me, in my mind, 'easy' is just two hours of really intense working."
Williams has not played a tour match since her semifinal defeat to Roberta Vinci at the U.S. Open. She withdrew from her first match at the Hopman Cup two weeks ago, then retired in her next match before withdrawing from the team tournament. However, she insisted the inflamed knee has improved in the intervening period.
"I just needed some time to get over that little hump," she said.
Williams begins against the top unseeded player in the draw, Camila Giorgi.
With so many titles and so much experience, the world No. 1 does not expect lack of play to be a problem going into the tournament.
"I've had a really good preparation,” she said. “I mean, I didn't have the match play that I've wanted to have. But after playing for so many years on tour, I should be able to, you know, focus on that."
Williams is a six-time champion at the Australian Open.
