MELBOURNE, Australia — Serena Williams reached her fifth Australian Open final Wednesday by beating China's Li Na 7-6 (7-4), 7-6 (7-1), her 50th win at Melbourne Park.
Williams dominated the second-set tiebreaker, clinching the match with an ace.
Li, who beat Venus Williams in the quarterfinals, saved three match points in the 10th game and one in the 12th.
"I had so many match points, and I blew it," Williams said. "And I knew I couldn't mess up my serve because she never gives up.
"She's a real, real amazing fighter."
Venus Williams, who had a chance to serve for the quarterfinal on Wednesday against Li before she lost, was watching from the stands. She was to partner Serena later in a women's doubles semifinal against Lisa Raymond and Rennae Stubbs.
In the first tiebreaker, Williams picked up four of her last five points on unforced errors and clinched the set with a second-service ace.
Williams has a perfect record in Melbourne Park finals, having won in 2003, 2005, 2007 and 2009. Saturday, she faces the winner of the late match between Justine Henin and China's Zheng Jie. Zheng, who reached the 2008 Wimbledon semifinals, seeks to become the first Chinese player to reach a Grand Slam final.
Meanwhile, with the only three men to beat Roger Federer in the past 19 majors already out, the Swiss star extinguished his most recent threat, beating Nikolay Davydenko 2-6, 6-3, 6-0, 7-5 to reach the semifinals.
Davydenko's 13-match win streak included victories over Federer at the season-ending tournament in November and season opener this month. But down 3-1 in the second, Federer won 13 consecutive games to reach his 23rd consecutive Grand Slam semifinal.
"Winning that many games in a row against a player that's been on fire like this, it's a great sign," Federer said.
No. 2-ranked Rafael Nadal, who beat Federer in the 2008 Australian Open final, 2008 Wimbledon final and 2006-08 French Open finals, retired with a knee injury while trailing Andy Murray in Tuesday's quarterfinals.
No. 3-ranked Novak Djokovic, who beat Federer in the 2008 Australian Open semis, lost 7-6 (10-8), 6-7 (5-7), 1-6, 6-3, 6-1 to Jo-Wilfried Tsonga earlier Wednesday.
And No. 4-ranked Juan Martin del Potro, who beat Federer in last year's U.S. Open final, lost to Marin Cilic in the fourth round. Cilic faced Andy Murray in the first men's semifinal this morning.
Federer, 28, said he was more concerned about who was still alive than who dropped out.
Davydenko had lost 12 consecutive matches to Federer before gaining some confidence with the wins. But to beat Federer, the Russian said, you have to be like him.
"You know, to be like perfect," he said. "He's No. 1."
Friday, Federer faces Tsonga, whose past two wins have come in the only five-set matches he has played in 11 Grand Slams. Djokovic complained of an upset stomach after the match.
"I saw he wasn't very good," Tsonga said. "But sometimes, he does that and he wins."