Ruthless Jankovic maintains course for top ranking

LOS ANGELES, California (Reuters) - Top seed Jelena Jankovic remained on course to become the world's top ranked player when she eased to a 6-3 6-2 triumph over Melinda Czink in the third round of the Los Angeles Classic on Thursday.

Victory at this event will allow the 23-year-old Serb to leapfrog her compatriot Ana Ivanovic in the world rankings and her task was made easier when third seeded Anna Chakvetadze was beaten by Sybille Bammer in three tough sets.

Russia's Vera Zvonareva also lost, the fifth seed falling 6-4 7-5 to countrywoman Nadia Petrova, who lined up a quarter-final showdown against Jankovic with the victory.

Playing her first tournament since injuring her knee at Wimbledon last month, Jankovic dominated her left-handed Hungarian opponent, controlling the rallies and sending down seven aces in a powerful display of serving.

"If I could hit this serve every day like that, my life would be so much easier," Jankovic told reporters.

"You don't have to break a sweat and you're winning games. There's no pain in my knee and I'm really happy about that."

Russia's Chakvetadze, however, suffered the pain of defeat and was clearly frustrated by her performance against the Austrian 14th seed following her 6-4 5-7 6-2 loss.

"She (Bammer) didn't do anything special," Chakvetadze said.

"She was just putting ball in the court and I was either making mistakes or hitting winners.

"It was like I was playing myself. I'm disappointed. I had an open draw in this tournament and I didn't take my opportunity."

The diminutive Russian spent much of the deciding set yelling at herself and cracking her racket on the ground.

Bammer advances to face 10th seed Flavia Pennetta in the quarter-finals after the Italian overcame Ai Sugiyama of Japan 7-6 6-3.

Another leading player given a hard time was Dinara Safina, the Russian fourth seed was forced to call upon all of her reserves to edge out Alla Kudryavtseva 7-6 0-6 7-6.

The French Open finalist staved off a match point in the 10th game of the third set with a booming service winner, before closing out the tiebreaker 7-3 with a similar blast after her opponent had committed two forehand errors.

"I just went for it," Safina said. "I stayed tough and pushed her."

Safina moves on to face eighth seed Victoria Azarenka of Belarus, who beat Samantha Stosur of Australia 6-4 7-6.

In other matches, China's Yuan Meng defeated lucky loser Melanie South of Britain 6-2 6-3 and will play American Bethanie Mattek, a 7-5 6-2 winner over Olga Govortsova of Belarus.

(Editing by John O'Brien)