China's Li Na upset seven-time Grand Slam winner Venus Williams in a three-set thriller on Wednesday to join compatriot Zheng Jie in the semifinals of the Australian Open.
The 16th-seeded Li came from one set down to beat the American sixth seed 2-6, 7-6 (4), 7-5, reaching the semi stage of Grand Slam events for the first time in her career.
"This is the best day of my whole life," the 27 year-old Li said.
It is also the first time two Chinese players have made the last eight of the same Grand Slam. The unseeded Zheng eased past Maria Kirilenko of Russia 6-1, 6-3 in her fourth-round clash on Tuesday.
Li will next face defending champion Serena Williams in the semifinal.
Venus Williams served for the match in the 10th game of the second set but once Li wound up her forehand and a cross-court backhand, there was no stopping her.
She forced the set into a tiebreaker and was aided in her quest to take the match into a third set with Williams errors on serve and groundstrokes.
In the final set it seemed no one wanted to win with nine breaks of serve in 12 games.
But Li gripped her racquet and gritted her teeth and hung tenaciously with Williams all the way.
"I know I lose first set but thanks for the coach - he never gave up," Li said looking towards her supporters' box with husband and coach Jiang Shan sitting alongside hitting partner Thomas Hogstedt and trainer Richard Sutton.
Although Zheng has reached a grand slam semifinal before in 2008 at Wimbledon, Li has made the quarterfinals twice before.
Since the Chinese pair are on opposite sides of the draw, they could conceivably meet in Saturday night's final.
"It's good for both players, it's good for Chinese tennis, and also good for the fans," Li said.
Zheng plays wild-card and grand slam champion on the comeback trail, Justine Henin in her semifinal.