Roger Federer and Serena Williams needed all their fighting qualities to remain in the Australian Open on Wednesday after Na Li stunned Venus Williams to become just the second Chinese to reach the semifinals of a Grand Slam.
Federer reeled off 13 games in a row to dig himself out of trouble and beat Russia's Nikolay Davydenko 2-6, 6-3, 6-0, 7-5 in a wildly fluctuating match.
Serena was also staring down the barrel in her quarterfinal against Victoria Azarenka of Belarus before she recovered to beat her 4-6, 7-6, 6-2. Her elder sibling might have joined her but threw away a match-winning lead in her 2-6, 7-6, 7-5 loss to Li, one of two Chinese women through to the last four at Melbourne Park.
Federer made it through to his 23rd consecutive Grand Slam semi but only after a titantic struggle with Davydenko, who won the opening set then got an early service break in the second.
“I've played him many times and I know he goes through phases, you just try to stay positive,” the Swiss said. He will now play Jo-Wilfried Tsonga, who fought back from two sets to one down to reach his first Grand Slam semifinal in two years by beating an unwell Novak Djokovic 7-6, 6-7, 1-6, 6-3, 6-1. The 10th-seeded Frenchman, beaten by Djokovic in the 2008 final here, was in trouble after the third set.
The Serb, however, was ill shortly after the fourth set began, temporarily leaving the court after telling chair umpire John Blom he needed to vomit.
The world number three returned but his game melted away and Tsonga was able to speed through the final two sets to win after three hours 52 minutes.