Serena Williams frightened a few people, including herself.
Defending champion Victoria Azarenka had a momentary lack of concentration.
Two of the biggest names on the men's side at the Australian Open - Roger Federer and Andy Murray - had straight-set wins.
Day Two at Melbourne Park on Tuesday brought another day of perfect weather but a few anxious moments for Williams, who fell awkwardly on her right ankle in her 6-0, 6-0 win over No. 110-ranked Edina Gallovits-Hall.
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.
"I heard she won love and love, so what kind of injury are we talking about?"
"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.
"I just had to really remain calm and think things through."
She left little doubt she'll be back to play her second-round match on 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."
Azarenka trailed 3-0 in the second set of her match with Monica Niculescu before leveling the set at 4-4 and winning 6-1, 6-4.
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?"
Murray, playing with more confidence since his U.S. Open win in the final over Novak Djokovic that ended a 76-year drought for British men in majors, beat Robin Haase of the Netherlands 6-3, 6-1, 6-3. The second-seeded Federer defeated Benoit Paire of France 6-2, 6-4, 6-1.
Murray needed just 1 hour, 37 minutes, and Federer 1:23 in their first-round matches. They'll need to conserve their energy for a potential semifinal against each other to determine a final against top-seeded and defending champion Djokovic, assuming all three men are still around on the final weekend.
Before a ball was hit on Tuesday, players and officials were shocked to hear of the serious illness and pending resignation of ATP World Tour executive chairman and president Brad Drewett. The ATP said in a statement on Tuesday that Drewett, a former player, has motor neurone disease, or Lou Gehrig's disease, but will continue in his role on an interim basis until a successor is found 'in the near future.'
Drewett has held the top ATP position since January 1 last year. The 54-year-old Australian was a top 40 singles and top 20 doubles player before he retired as a player in 1990.
Federer, president of the ATP Player Council, said the news was difficult for the tour and its players.
"I saw him yesterday and he told me the news," Federer 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"
"Obviously very emotional..."
It was Murray's first Grand Slam match as a major champion.
"It didn't feel much different to me," he said.
"I was still nervous before I went on to play the match.
"The benefits of that is if I get myself deep into a Slam this year and you're playing against the top players - that's when you'll draw on that experience and use it in the right way.''
In other men's matches, No. 6 Juan Martin del Potro, 2008 finalist Jo-Wilfried Tsonga, No. 13 Milos Raonic of Canada, who beat Jan Hajek 3-6, 6-1, 6-2, 7-6 (0), No. 14 Gilles Simon, No. 17 . Philipp Kohlschreiber, No. 21 Andreas Seppi and No. 25 Florian Mayer advanced.
Local hope Bernard Tomic, who beat Djokovic at the Hopman Cup two weeks ago, defeated Leonardo Mayer of Argentina 6-3, 6-2, 6-3 in a night match.
Tomic has been on a New Year's high after winning his first ATP tournament on Saturday at the Sydney International.
Frenchman Gael Monfils beat No. 18 Alexandr Dolgopolov of Ukraine 6-7 (7), 7-6 (4), 6-3, 6-3, and Finland's Jarkko Nieminen ousted No. 19 Tommy Haas 7-6 (3), 4-6, 6-3, 4-6, 8-6.
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 played this tournament with so many injuries and was able to come off pretty on top," she said.
"So for me, it's just another page and a great story to tell the grandkids one day."
In other women's matches, 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.