MELBOURNE, Australia — Serena Williams saved some family pride today at the Australian Open.

After her older sister Venus' upset loss to China's Li Na in the previous match on Rod Laver Arena, four-time champion Serena was down a set and 4-0 in the second before she rebounded for a 4-6, 7-6 (4), 6-2 win over Victoria Azarenka of Belarus.

Top-seeded Roger Federer overcame an awkward start to win 13 straight games and beat Nikolay Davydenko 2-6, 6-3, 6-0, 7-5 to reach the semifinals for a 23rd straight Grand Slam.

"It's incredible, looking back on how many years that is now, I'm able to deliver at Grand Slam play," Federer said. "For some reason I was just a bit worried I was not going to make it this time in the semis.

"Now obviously that it's safe again and I've been able to add one. Definitely one of the most incredible things I have in my resume."

Third-ranked Novak Djokovic has lost to Frenchman Jo-Wilfried Tsonga in an Australian Open quarterfinal that reversed the result of their final here two years ago.

The 10th-seeded Tsonga won 7-6, (8), 6-7 (5), 1-6, 6-3, 6-1 in the night match. After his win in 2008, Djokovic has been eliminated in the quarterfinals two years in a row.

Andy Murray and Marin Cilic are already through to the semis from the other half of the draw.

Venus Williams couldn't make it to an expected sister semifinal, losing in a mistake-filled match featuring in a combined 110 unforced errors against Li.

The result is that Serena will take on Li, who beat Venus 2-6, 7-6 (4), 7-5. Justine Henin, playing in her first Grand Slam tournament in two years after coming back from a two-year retirement, will play Zheng Jie in the other semifinal.

Serena Williams was far from confident after the first hour of the match, thinking of her sister's loss.

"It was obviously on my mind," Serena said of Venus' defeat. "I saw maybe one or two points, maybe three. I don't want to watch too much, I get too nervous watching. Obviously I was incredibly disappointed."

Instead of wilting, she fought back from her big deficit in the second set with two service breaks of her own, easily won the tiebreaker and dominated the third.

"I think it's impressive the way she does it," Azarenka said. "She's a strong girl. She has very powerful shots."

Li and Zheng were the first Chinese pair to reach the quarterfinals at the same Grand Slam. Add semifinals now, and could the final be possible?