Impressive Jankovic eyes Slam title and return to the top

Jankovic, who also lost the first set to Wozniacki this year at Wimbledon, broke again to finish the second set and again in the fourth and sixth games of the third set to secure the triumph.

"I'm getting better each day. I'm improving on my fitness," Jankovic said. "I can push off better. Little by little I'm putting the pieces together. I'm bringing my game to the next level. I believe in myself."

Olympic champion Dementieva, who can take the top spot if she reaches her first Grand Slam final since the 2004 US Open, defeated China's Li Na 6-4, 6-1 in just 61 minutes.

"This is a dream for me, to become number one, but I'm not thinking about it. I want to focus on this tournament," Dementieva said. "I don't want to put all this pressure on myself."

The Russian fifth seed booked a quarter-final date against Swiss 15th seed Patty Schnyder, who rallied to defeat Slovenia's Katarina Srebotnik 4-6, 6-3, 6-3. Dementieva says she is rounding her game into top form after the Olympics.

"I played very well in Beijing," she said. "Because of the recovery I don't think I'm playing at my best but I am slowly improving and I hopefully will play better in the next match."

Bammer ousted French 12th seed Marion Bartoli 7-6 (7/3), 0-6, 6-4 with Bartoli weakened by a sick stomach and defying doctor's advice not to play because of low blood pressure.

"It's a miracle I could manage three sets," Bartoli said.