MELBOURNE, Australia -- Serena Williams cautiously walked onto the court, and tried to keep the points short to avoid irritating her injured right ankle as she advanced to the third round at the Australian Open.
Apart from a swollen lip from hitting herself in the face with her racket in the sixth game, she emerged unscathed.
Summoning all her experience from 15 major titles, including the final two of the last season, Williams lifted her tempo on the biggest points -- winning an 18-minute game to open the second set, finally cashing in on her fourth break chance.
Nineteen minutes later, she finished off a 6-2, 6-0 win Thursday over No. 112-ranked Garbine Muguruza with an ace at 128.7 mph -- the fastest she can remember serving.
"I'm on the up and up, I feel. It can only get better from here," she said, adding that she wasn't bothered by the ankle during the match.
"Obviously when you go out to play you're heavy on adrenaline and you're really pumped up," she said. "Usually I feel injuries after the match but so far, so good. I felt pretty, much better than I ever dreamed of expecting to feel."
Following the match, Williams tweeted: "What was that? That was 207km yes 128mph serve! Wha wha whatttt chu say??!!!! Whoop whoop!"
Williams said she was bleeding from the lip at one stage, "But it's OK. It's a war wound."
"I think it happens to everyone, but I have never busted it wide open like that," she said. "So, yeah, I was like, 'Oh, no. I can't have a tooth fall out.' That would be horrible."
Despite the injury concerns ever since needing medical timeout to treat her ankle during her first-round win on Tuesday, Williams planned to play doubles later with sister Venus, and will play her next singles match against Japan's Ayumi Morita on Saturday.
Defending champion Victoria Azarenka practically danced into Rod Laver Arena for the match before Williams' victory, and said she's starting to find some rhythm after beating Eleni Daniilidou 6-1, 6-0 in 55 minutes.
With temperatures expected to top 102 degrees, Azarenka didn't want to be out in the heat.
"I felt like I'm back into the competitive mode," she said. "I was really focused -- that was for sure the best part of the game for me."
The No. 94-ranked Daniilidou only won 10 points in the first set and was shut out in the second despite having triple break point in the fourth game.
Top-ranked Azarenka had her friend and musician RedFoo in the stands watching and signing autographs, and said she went onto the court listening to a "great mix of disco music and a little bit of new music. I really start to like it a lot -- there's no words really."
The 23-year-old Belarusian won her first Grand Slam title in Melbourne last year, during a 26-match winning streak to start the season.
"It's pretty difficult to duplicate something like that," she said. "All I can do is try."
She didn't win another major in 2012, dropping the U.S. Open final against Serena Williams, but held the No. 1 ranking for most of the season.
The temperature hit 93 degrees during the first match of the day, and went above 104 later in the afternoon. Players wore ice vests and were shielded by umbrellas during the breaks in play.
The Melbourne-born Robson, who won a mixed doubles silver medal at the London Olympics last year with Murray, trailed 3-0 in the final set before coming back to win a match featuring 14 service breaks -- seven by each player. Robson served for the match twice, failing to clinch it at 6-5 before getting another chance eight games later.
The 10th-ranked Wozniacki was the No. 1 player in the world here last year, but faced criticism that she had never won a Grand Slam.
She failed to change that in 2012, losing in the quarterfinals at Melbourne Park, the third round at the French Open and the first rounds at both Wimbledon and the U.S. Open.
Other women advancing included No. 14 Maria Kirilenko, No. 16 Roberta Vinci, No. 20 Yanina Wickmayer and Elena Vesnina, who beat No. 21-seeded Varvara Lepchenko of the United States 6-4, 6-2. Former U.S. Open champion Svetlana Kuznetsova beat 26th-seeded Hsieh Su-wei of Taiwan 6-2, 6-1.
Women's No. 2 Maria Sharapova overwhelmed Japan's Misaki Doi in 47 minutes, even less time than she needed to beat fellow Russian Olga Puchkova two days earlier in her first competitive match of 2013.
The first woman to post back-to-back 6-0, 6-0 wins at a Grand Slam since 1985 next plays seven-time major winner Venus Williams in the third round.
"It's not really the statistic I want to be known for," Sharapova said. "I want to be known for winning Grand Slams."
Sharapova leads the head-to-head series 4-3 against Venus Williams, but Williams has won both of their Grand Slam meetings.
Venus is still on the comeback trail after missing seven months after the 2011 U.S. Open to deal with Sjogren's Syndrome.
Now seeded 25th, she dropped only one game in her first-round win and then went down a break early to Alize Cornet of France before winning 6-3, 6-3.
The biggest upset Wednesday was 2011 U.S. Open champion Samantha Stosur's 6-4, 1-6, 7-5 loss to China's Zheng Jie.
Stosur led 5-2 in the third and wasted two chances to serve out the match, finally giving it away with a double fault on match point.
Information from The Associated Press was used in this report.