Williams routed Gallovits-Hall 6-0, 6-0 in the first round of the Australian Open on Tuesday despite the scary sequence in the first part of the match.
The No. 3-ranked Williams is favored to win the season's first major, rolling into Melbourne Park with 35 wins in her previous 36 matches, including titles at Wimbledon, the London Olympics and the U.S. Open. But the injury could be a significant setback as she seeks a third consecutive Grand Slam title.
Williams had the ankle heavily taped by trainers and was able to continue and still dominate the Romanian player. Later, she said she hoped to continue playing -- she'll have a scheduled day off Wednesday, returning Thursday to play her second-round match -- and maintain her quest of winning her third Grand Slam tournament in a row and sixth Australian Open.
She left little doubt she'll be back to play her second-round match Thursday against Garbine Muguruza of Spain, who needed a 14-12 win in the deciding set to clinch her first-round match Tuesday against Magdalena Rybarikova of Slovakia.
"Oh, I'll be out there," Williams said of her second-round match. "I'm alive. My heart's beating. I'll be fine."
Williams sounded almost matter-of-fact about her ankle ailment and its potential to affect her play in the rest of a Grand Slam she has won five times.
"I've been injured before," she said. "I've played this tournament with so many injuries and was able to come off pretty on top. So for me it's just another page and a great story to tell the grandkids one day."
"I started well but I struggled a little in the second set," Azarenka said.
Told that her biggest threat on her half of the draw had injured her ankle, Azarenka wondered, tongue-in-cheek, how serious Williams' ailment could be: "I heard she won love and love, so what kind of injury are we talking about?"
With a packed program on the center court, Williams was playing on the second of the show courts.
The 31-year-old American was leading 4-0 after 19 minutes when she fell awkwardly chasing a ball wide on her forehand side, putting both hands over her face.
She rolled from her back to her hands and knees, where she stayed for several minutes before she was helped to her feet. The 15-time major winner started limping before easing into a walking stride as she made her way to her court-side chair to have her already heavily taped ankle treated and then retaped.
"I think I was really, really close to panicking because a very similar thing happened to me last year, almost on the same side, the same shot," Williams said. "So I almost panicked, and I thought, 'I can't do that. I just have to really remain calm and think things through.'"
Williams won the first point after the medical timeout, approaching the net to hit a cross-court winner, seemingly unfazed by the ankle. She hit two more forehand winners to go up 5-0, then called the trainer back to the court to adjust the taping on the ankle during the changeover. She had more treatment after winning the first set.
Williams winced slightly after jumping to hit an overhead in the third game of the second set and called the trainer out again to retape the ankle during the changeover, leading 3-0.
She dominated the second set despite the injury, allowing the Romanian player to win just six points.
Williams is favored to win the season's first major, coming into Melbourne with 35 wins in her previous 36 matches, including titles at Wimbledon, the London Olympics and the U.S. Open.
Venus Williams congratulated her sister later, tweeting: "Wow, @serenawilliams is so awesome, to finish her match with injury with out loosing a game, a true champ!"
After her match, Date-Krumm fielded a variety of questions about her secret to longevity in a sport filled with women half her age.
"Some players' mothers are younger than me," she laughed. "So it's like (they're) my daughter."
Her advice to keeping fit: "I sleep a lot. I eat healthy foods. I drink a lot," she said. Bedtime is usually before 10. "It's a simple life, that's it. Nothing special."
The mindset that comes with her age has helped her, she said, as did a long period of absence from the sport.
Date-Krumm, who is married to German race car driver Michael Krumm, took a 12-year break from tennis and returned in 2008.
Also, former No. 1-ranked Caroline Wozniacki won the last six games to beat Sabine Lisicki of Germany 2-6, 6-3, 6-3 to advance along with No. 16 Roberta Vinci, No. 17 Lucie Safarova and No. 29 Sloane Stephens, the American teenager who beat Simona Halep of Romania 6-1, 6-1.
Former U.S. Open and French Open champion Svetlana Kuznetsova continued her comeback from a knee injury that kept her out of the U.S. Open, ending her run of 40 consecutive majors. Also, No. 14 Maria Kirilenko had a 6-4, 6-2 win over American player Vania King.
Two seeded players lost night matches. Julie Hampton of the U.S. beat No. 31 Urszula Radwanska of Poland 6-2, 6-4 while Ukrainian qualifier Lesia Tsurenko defeated No. 24 Anastasia Pavlyuchenkova of Russia 7-5, 3-6, 7-5.
While Serena Williams will have the day off to rest her weary ankle Wednesday, her sister Venus will be back in action against Alize Cornet of France.
Information from The Associated Press was used in this report.