(CNN) -- Four-time champion Serena Williams survived an early injury scare to cruise into the second round of the Australian Open on Tuesday.

The American third seed rolled her ankle when 4-0 up in the opening set of her match with Romania's Edina Gallovits-Hall, but retained her composure to seal an emphatic 6-0 6-0 "double bagel" triumph.

"I haven't had enough time to assess it yet," the 15-time grand slam champion told reporters after arriving at her press conference on crutches. "I saw the doctor again -- we're just going to see how it is in a few hours from now.

"But I'll be out there on Thursday -- I mean, unless something fatal happens to me -- there's no way I'm not going to be out there competing. I'm alive. My heart's beating. I'll be fine."

Williams' second-round opponent will be Garbine Muguruza, who survived a marathon third set against Slovakia's Magdalena Rybarikova to seal a 4-6 6-1 14-12 win.

The 31-year-old also injured her ankle last year, at the Brisbane warmup tournament, and then lost in the fourth round in Melbourne.

"It reminded me a lot of Brisbane. I thought, 'Oh, not again.' But, you know, I've had such a good year that I don't think it's anything negative," she said.

"I've been injured before. I've played this tournament with so many injuries and was able to come out on top.

"So for me, it's just another page, and a great story to tell the grandkids one day."

Top seed Victoria Azarenka also advanced at the expense of a Romanian, recovering from 0-3 down in the second set to beat the unseeded Monica Niculescu 6-1 6-4.

"Her game is definitely unusual, but I've known her since we played Under 14s, and she actually played a lot more spin back then -- it was all slice from both sides before," said the defending champion, who will next play Greece's Eleni Daniilidou.

"Monica's unusual and tries to make you feel a little bit miserable on the court, like you don't know what to do, because every ball comes from different angles. So it's important to just keep your focus and execute your shots."

Two grand slam champions went head-to-head in the Margaret Court Arena, with 2011 Wimbledon winner Petra Kvitova edging past Italy's Francesca Schiavone -- who clinched the 2010 French Open title.

Czech eighth seed Kvitova battled to a 6-4 2-6 6-2 win to set up a tie with British Olympic mixed doubles silver medalist Laura Robson.

Japan's Kimiko Date-Krumm made history by beating Russian 12th seed Nadia Petrova 6-2 6-0, becoming the oldest player to win a match at the Australian Open.

The 100th-ranked 42-year-old broke a record previously held by Britain's Virginia Wade.

"Playing at this age is really nothing," explained Date-Krumm. "I eat a lot, I sleep a lot -- last night I was in the bed before 10 p.m. I finished dinner at 7:30 already, then sleep before 10 like the kids!

"Because after practice or after matches I'm always tired, so I just need to recover more. It's a simple life. Nothing special.

"Of course I'm very happy to win today, but I don't play for records. Even if I lose, I still enjoy it."

Italian seventh seed Sara Errani also fell at the first hurdle. The 2011 French Open finalist lost 6-4 6-4 to Spain's Carla Suarez Navarro.

In the men's draw, four-time champion Roger Federer cruised through his opener against France's world No. 46 Benoit Paire, winning 6-2 6-4 6-1 in just 83 minutes.

The second seed paid tribute to ATP Tour chief Brad Drewett following Tuesday's news that he will stand down as head of men's tennis after being diagnosed with the motor-neurone disease.

"I saw him yesterday and he told me the news. I've known Brad ever since I came on tour ... I call him a friend," said Federer, who is looking for an Open era-record fifth win in Melbourne.

The Australian, a former tennis pro, has played a key part in expanding the men's game into Asia, taking the season-ending championships to Shanghai before it switched to London in 2009.

"He was so influential. He goes so far back and has touched so many people throughout his career as a player and then also as an executive and then CEO," Federer said.

"It's been very hard to see him not doing so well, so we wish him the best. I worked with him very closely, especially the last few years now, and he deserved to be CEO and chairman."

Federer will play fellow 31-year-old Nikolay Davydenko in round two after Russia's world No. 40 defeated Israel's Dudi Sela.

U.S. Open champion Andy Murray began his bid for a third final appearance in four years at the Melbourne grand slam with a comfortable 6-3 6-1 6-3 win against Dutchman Robin Haase.

Haase saved two match points, but world No. 3 Murray -- beaten by Federer in the 2010 final and Novak Djokovic last year -- shrugged off any suggestion nerves were negatively impacting his game.

"If you aren't nervous, it shows that you're really not that bothered," said the 25-year-old Murray after setting up a meeting with Portugal's Joao Sousa.

"When the nerves are there, sometimes it can be for 10, 15 minutes before you go on the court or the beginning of the match or the evening beforehand. They can affect you at different times.

"But it shows that you care, and that's the positive you take out of it. Often when you are nervous, you can play your best tennis."

Fifth seed Jo-Wilfried Tsonga advanced at the expense of fellow Frenchman Michael Llodra, sealing a 6-4 7-5 6-2 success. Next up for the 2008 runner-up is Japan's Go Soeda.

Canada's 13th seed and rising star Milos Raonic eventually hammered down 104th-ranked Czech Jan Hajek, smashing 30 aces to card a 3-6 6-1 6-2 7-6 (7-0) win in two hours and 35 minutes.

He will next face fellow big server Lukas Rosol, famous for defeating Rafael Nadal at Wimbledon 2012.