By Martyn Herman

LONDON (Reuters) - Madison Keys, the woman tipped as the most likely American successor to the Williams sisters, powered to a 6-4 4-6 6-3 victory over Kirsten Flipkens in the second round of Wimbledon on Thursday.

The ninth seed, a quarter-finalist last year, suffered a second-set blip against the experienced Belgian, and wavered again late on having roared into a 5-0 lead in the decider.

But she managed to nip the Flipkens comeback in the bud and will face Frenchwoman Alize Cornet in the next round.

Keys boasts the kind of destructive weapons ideally suited to grass, particularly a first serve that three-times Wimbledon champion Chris Evert describes as a match for the booming delivery of world number one Serena Williams.

It was not at its best against Flipkens, however, and she dropped serve three times in the match, although the 34 groundstroke winners she crunched kept her largely in control.

She suffered jitters in the third set, missing a backhand on match point when serving at 5-1 and dropped serve.

When world number 51 Flipkens held to trail 3-5 an unlikely comeback looked possible, but Keys kept calm and sealed victory when she forced her opponent into an error.

"I think at times I was a little bit too passive, which is why she was able to get back in the match and win that second set," Keys said.

"When I was playing well, I was definitely more aggressive."

Keys, one of 18 Americans in the women's singles draw, arrived at Wimbledon having won the grasscourt warmup event in Birmingham -- a second career title and a second on grass that propelled her into the top 10 for the first time.

Surprisingly she is the first American woman to crack the top 10 for the first time since 21-times grand slam champion Serena Williams in 1999.

Older Williams sister Venus, 36, is also in the top 10, meaning three American women are there for the first time since September 2005 when the sisters were joined by Lindsay Davenport.

Asked about five-times Wimbledon champion Venus's longevity, Keys said: "I know she had a lot of health issues. So being able to get through all that and still be one of the best women in the world is really inspiring."

Fellow American Sloane Stephens, who burst on to the scene before Keys but has seen her career level off, is a round back after the 18th seed won a rain-delayed first round against China's Peng Shuai.

(Reporting by Martyn Herman; editing by Ed Osmond)