Williams had strained a hip muscle and later said she was in so much pain that if she hadn't been playing in a Grand Slam, she likely would have retired from the match.
Instead, she took a medical timeout, had her upper right thigh wrapped and rallied for a 6-7 (6), 6-0, 6-4 second-round win Wednesday over Czech opponent Sandra Zahlavova. That kept intact her streak of 257 straight singles matches at majors without a retirement.
"This being a major definitely has a lot to do with me staying on the court," Williams said. "Obviously, I wasn't able to play at my exact level, so I had to play smarter and hang tough."
Her mother, Oracene Price, had yelled encouragement to "fight" during the tiebreaker at Rod Laver Arena.
Williams, the winner of seven Grand Slam singles titles, managed to track down most of the angled shots from Zahlavova in the second set despite the injury. The 97th-ranked Zahlavova didn't win a game in the set.
Williams was able to hit winners from the baseline, relying on her powerful groundstrokes to keep rallies short. The fifth-ranked Williams broke Zahlavova's serve in the seventh game of the third set and served out the match.
The 30-year-old Williams isn't sure how the injury will respond to treatment before her next match against 33rd-ranked Andrea Petkovic of Germany.
"I'm going to try to recover for Friday and get ready to play and bring my best tennis," she said. "Hopefully, I can come through."
She needed assistance after the match, asking courtside staff and officials to help carry her equipment bag and rackets.
Williams carried her handbag, which went with her outfit — a lattice-style top with a multicolored satin short skirt she later referred to as her "Alice in Wonderland" outfit.
"It was really tough, but I'm a long way from home and it's such a long way I didn't want to go back yet," Williams said. "You've got to be able to play under all kinds of circumstances — good, bad, strange, weird, all of the above.
"When I look back, I have no regrets that I could have done more or I could have done less. For me, it's peace of mind. I think what keeps me going is knowing that when I'm healthy, I play really, really well."