MELBOURNE, Australia -- Serena Williams got on and off court as quickly as she could in the scorching heat Friday, registering yet another record with match win No. 61 at the Australian Open as she advanced to the fourth round with a 6-3, 6-3 victory over Daniela Hantuchova.
The five-time Australian Open champion later withdrew from the doubles and will not have to face any extra exposure to the blazing sun during the once-in-a-century heat wave gripping Melbourne for a fourth straight day.
Two-time finalist Li Na, the major threat to top-ranked Williams in the top half of the women's draw, had to save a match point before coming back to beat No. 26-seeded Lucie Safarova 1-6, 7-6 (2), 6-3 in 2 hours, 37 minutes.
Li, the 2011 French Open champion, later joked that she needed the match practice "because I think the weather is not warm enough."
Li knew she was lucky to stay another round.
"I think five centimeters saved my tournament," she said, indicating with her fingers how close Safarova's shot at break point in the second set had been to sending her home. "If she hit in, I think, the whole team is on the way to the airport."
Williams didn't face any serious danger in her win over No. 31-seeded Hantuchova, whose only win in 10 head-to-head matches came in the corresponding round at the 2006 Australian Open.
Williams was off the court in 1 hour, 20 minutes, and has conceded just 12 games in three straight-set wins this week.
She equaled Margaret Court's Australian Open mark of 60 wins with her second-round victory and beat that in the third round when she also matched Lindsay Davenport's record of 69 main-draw matches here in the Open era. That means she'll set another record just by showing up Sunday against former No. 1-ranked Ana Ivanovic.
Ivanovic ended Samantha Stosur's hopes of again making a credible showing in her home Grand Slam when she beat the 2011 U.S. Open champion 6-7 (8), 6-4, 6-2 on Friday night in the third round of the Australian Open.
It was the 10th time in 12 attempts that Stosur has failed to advance past the third round at the Australian Open. She lost in the second round last year and the first round in 2012.
Stosur clinched the first set Friday on her seventh set point after coming back from a delay due to rain that forced the roof at Rod Laver Arena to be closed.
Ivanovic dominated the last two sets to set up a fourth-round match against top-ranked Williams.
"It was a tough match. ... It's definitely hot, but you have to be ready to play," Williams said of her match with Hantuchova. "And then you have to prepare yourself mentally, too."
The temperature hit 102 Fahrenheit during Williams' match and topped 108 degrees by mid-afternoon, but humidity remained low and organizers did not invoke the extreme heat policy and suspend matches for the second day in a row. The temperatures dipped to 90 degrees before the night matches as a cool change kicked in.
Williams has won 24 matches dating back to August, carrying momentum from her dominating 2013 into a new season. She won 78 of her 82 matches and won 11 titles last year, and seems to be getting better with age.
"I feel like, in life 32 is young. In sports it's old," she said. "But for whatever reason, I feel like I just never was really able to reach my full potential, and I feel like recently I just have been able to do a little better. I just keep trying to improve on everything."
The Williams sisters were entered in the doubles but withdrew after Serena's singles match Friday, citing a left leg injury for Venus.
"I love playing doubles, love playing with Venus, but sometimes it doesn't work out," Serena said. "I guess it's a relief, but like I say, we love to play doubles and we love to be out there ... so I'll definitely miss it."
Rod Laver Arena was about three-quarters full for Serena Williams' match Friday, although it was a quiet crowd -- people seemed to be expending more energy fanning themselves with programs and newspapers than applauding points on the court.
No. 9 Angelique Kerber advanced earlier with a 6-3, 6-4 win over American Alison Riske and said her main aim had been to "get off the court before it became really hot." Kerber will next play No. 28 Flavia Pennetta, who advanced 6-1, 7-5 over Mona Barthel of Germany.
No. 22 Ekaterina Makarova advanced with a 6-4, 6-4 win over Monica Niculescu, and No. 30 Eugenie Bouchard beat American Lauren Davis 6-2, 6-2 to set up a fourth-round match against Australian wild-card entry Casey Dellacqua, who beat 2010 semifinalist Zheng Jie of China 6-2, 6-4.
The Associated Press contributed to this report.