The French Open champion had trailed 3-1 in the first set and 4-1 in the second, before securing the straight-set win and a berth in the quarterfinals, where she will meet Russian Anastasia Pavlyuchenkova, who downed Italy's Roberta Vinci 6-2, 6-4, yesterday.
Marion Bartoli, seeded foruth, also progressed to the last eight, beating Czech Klara Zakopalova 6-2, 2-6, 6-1. The Frenchwoman will next face another Czech: qualifier Petra Cetkovska.
Unseeded Spaniard Anabel Medina Garrigues moved into the quarters, overcoming a knee injury to win 6-2, 7-6 (5) win over Elena Vesnina of Russia. Her next opponent will be Italian Francesca Schiavone.
Li, the first Asian to win a Grand Slam event, has beaten Kirilenko four of the five times they have met. But, she said, the Russian, like most of her opponents since the French Open, seemed to be a bit more focused this time.
"Everyone thinks different," she said. "Before (it was), ''Oh, OK, I beat her.'' But now, if they win, ''Oh, I beat a French Open champion.'' They are even more excited."
Li took the first set after breaking Kirilenko in the seventh game, which went to deuce four times. She also broke Kirilenko in the seventh game of the second set to get back on serve. She then won four straight points in the tiebreaker for a 6-2 cushion.