MELBOURNE, Jan. 17 -- Two Chinese players struggles at Friday's Australian Open. Two-time runner-up Li Na fought back to reach the fourth round while Zheng Jie lost to Aussie wildcard Casey Dellacqua.

Fourth seed Li Na saved a match point and survived a scare from 26th seeded Lucie Safarova of the Czech Republic at 1-6, 7-6(2), 6-3, avoiding becoming the highest ranked casualty in the first week of the tournament. Li saved a match point in the 12th game of the second set and forced a tiebreak, in which the China's No. 1 clinched 7-2 to send the match into a decider.

The 2011 French Open champion broke in the eighth game of the third set and then held serve to set up a fourth round clash with Ekaterina Makarova of Russia.

Safarova made the most of Li's double faults to get a break in the first game then held for a 2-0 lead. Li held her next serve to stay in touch but Safarova pushed Li around and gained another break.

Safarova held for a 5-1 lead and broke again to take the first set 6-1 in 27 minutes, with Li hitting only two winners and making 18 unforced errors in the set.

Safarova served for the match in the ninth game of the third set but Li finally seized the chance to break back and stay in the tournament after wasting two break points.

They exchanged breaks in the final set. Safarova smashed a forehand into the net in the eighth game and put Li in front. And the Chinese served for the match.

Zheng Jie lost to Dellacqua in straight sets. The Aussie raced through the first set in 33 minutes and broke Zheng's serve again in the opening game of the second set. Zheng, a former Australian Open and Wimbeldon Open semifinalist, got back on level terms.

But the Chinese took a five-minute medical timeout to be treated for heat stress after the seventh game.

Though she dropped her serve immediately after the resumption, 28-year-old Dellacqua broke straight back and then served the match out.

Zheng miscued several shots, recording 28 unforced errors and had her serve broken five times during the match.

Top seed Serena Williams blew past Slovak Daniela Hantuchova in straight sets and set a record of 61 Australian Open match wins. The American was off the court in one hour and 20 minutes and had conceded just 12 games in three straight-set wins this week.

She equalled 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, which means she'll set another record just by showing up on Sunday.

In men's singles event, No. 7 seed Tomas Berdych of Czech Republic beat qualifier Damir Dzumhur in straight sets and set up a fourth round meet with South African Kevin Anderson while Spaniard David Ferrer defeated Jeremy Chardy of France 6-2, 7-6(5) and 6-2.