Tennis: Serena winds up her game to fend off Sharapova as Clijsters beats Henin

Ahead of their much-anticipated rematch, Maria Sharapova was insistent that Williams' power could be harnessed but in the scorching sunshine at SW19, the American turned up the heat – and the Russian wilted.

Sharapova did however, stand toe-to-toe with Williams in a breath-taking 57-minute first-set with Williams winning 7-6 (9), 6-4.

They traded blow after blow and Williams' early break was swiftly nullified by Sharapova with a break of her own before a gruelling tie-break ensued.

Sharapova was not without her chances and hadthree set-points of her own, but

Williams ground out the first set before a solitary break and her blistering serve saw her through the second to set up a last-eight clash with ninth seed Li Na of China.

"It was definitely tense out there," she said. "She's so good and she's mentally focused and she's in it for every point.

"Even on match point she was trying 200 per cent. I honestly feel like I've had tough matches against everyone so far. And now I'm playing another tough player. Li Na always gives me a run for my money."nt."

Meanwhile, Kim Clijsters proved victorious in the battle of the Belgians, overcoming compatriot Justine Henin 2-6, 6-2, 6-3.

Henin, who also took a lengthy break from tennis, eased through the first set as Clijsters, seeded eighth, made a host of errors but Henin fell and injured her arm in the first set and opened the door for Clijsters. "I was just very overwhelmed in the beginning by the speed of her game. She was definitely overpowering me on every aspect of the match," said Clijsters. "So I was happy to get through there in the end I played really good tennis."

Elsewhere, Venus Williams was forced to dig deep to book a quarter-final place with a 6-4, 7-6 (5) win over unseeded Australian Jarmila Groth.