Pennetta has played the best tennis of her career since returning last year from a wrist injury, which caused her ranking to drop as low as No.166. Back to the court from injury, the Italian reached her first Grand Slam semifinal at the U.S. Open and then her first quarterfinals at the Australian Open.
"It was good. I'm happy about this tournament. I play a few matches in a good way. I enjoy to play here in Australia," said Pennetta. "Of course I'm a little bit upset because I would like to play a little bit better today. But next week I have another tournament and everything starts again."
It will be Li's fourth semifinals in five years at the Melbourne Park. She will play against 30th-seeded Canadian teenager Eugenie Bouchard, who stunned No.14 seed and former world No.1 Ana Ivanovic of Serbia 5-7, 7-5, 6-2.
Bouchard, who turns 20 next month and is exactly 12-year younger than Li Na, reached her first Grand Slam semifinals in just four appearances. Her previous best result was making into the third round in Wimbledon Open last year.
The absence of top seed Serena Williams opens the draw for Li. Williams was defeated by Ivanovic in the Sunday's fourth round.
Although Li claimed her only major title to date three years ago at the French Open, it is at Melbourne Park where she has performed most consistently at Grand Slam level.
She lost the 2011 and 2013 finals to Kim Clijsters and Victoria Azarenka and also reached the Australian Open semis in 2010.
Li Na's way to semis
