Madrid - World number two Li Na came from a set down to beat 16th seed Sloane Stephens 2-6, 6-3, 6-2 to reach the quarter-finals of the Madrid Open on Thursday.
The Australian Open champion had no answer to Stephens's power in the first set as she dropped her first set of the week.
However, she responded well to take the next two sets and set up a meeting with four-time Grand Slam champion Maria Sharapova or Australian Sam Stosur in the last eight.
Latest results from the sixth day of the combined ATP Madrid Masters and WTA Madrid Open on Thursday (x denotes seeded player):
Petra Kvitova (CZE x5) bt Lucie Safarova (CZE) 6-4, 6-3
Li Na (CHN x2) bt Sloane Stephens (USA x16) 2-6, 6-3, 6-2