China's Li Na defeated Czech Iveta Benesova 6-1, 6-4 on Wednesday to move into a third-round match-up at the Madrid Masters against Italian Roberta Vinci.
Australian Open finalist Li has revitalised her tennis this week on the clay in Spain, winning her third match from eight played since losing the Melbourne final to Kim Clijsters in late January.
Li's next opponent, Vinci, is fresh from a title in Barcelona at the weekend and reinforced her current form with a second-round defeat of Russian Alisa Kleybanova 6-2, 6-2.
Li is playing on a career-high ranking of sixth and needs one more victory to duplicate her Madrid best of a 2010 quarter-final. She improved to a career 4-0 over the 65th-ranked Benesova.
Li secured her win in 58 minutes with five aces and three breaks of serve.
In the third round, Czech 16th seed Petra Kvitova upset second seeded Russian Vera Zvonareva 6-1, 6-4 to earn the first of the quarter-final spots at the Caja Magica.
The winner owns titles this season at Brisbane and the Paris Indoors in a sizzling start to the year. She will face the winner from eighth seed Maria Sharapova and Slovak Domenika Cibulkova.
In the men's second round, Frenchman Michael Llodra beat Flavio Cipolla 6-4, 6-2 after the Italian had eliminated American Andy Roddick. Brazil's Thomaz Bellucci advanced as German Florian Mayer to hand over a 6-7 (5/7), 6-3, 3-0 victory.