Russia's Maria Sharapova gestures after winning her singles match against Japan's Ai Sugiyama at the Wimbledon tennis championships in London, June 30, 2007.

(Xinhua/Reuters Photo)

Photo Gallery>>>LONDON, June 30 (Xinhua) -- Defending champion Amelie Mauresmo and second-seeded Maria Sharapova eased to the fourth round of the Wimbledon tennis championships before rain halted play at the grass court grand slam on Saturday.

Mauresmo was not troubled at all as she hammered Mara Santangelo 6-1, 6-2 to book her place in the last 16 at a rain-hit All England Club while the 2004 champoin Sharapova set up a potential fourth-round clash with fellow former champion Venus Williams as she powered past Ai Sugiyama 6-3, 6-3 on Court One.

Much of the day had seen the famous green covers repel the rain at SW19, but Mauresmo wasted little time when the showers briefly stopped.

The fourth seed took just 25 minutes to win an indistinguished first set 6-1 on Center Court, and 32 minutes later it was all over. She will face Nicole Vaidisova or Victoria Azarenka next.

Santangelo, ranked 29th, failed to match her opponent's speed and power on Centre Court. Mauresmo broke serve at her first opportunity and struck 21 winners to the Italian's 11, often finishing the point with a volley.

Mauresmo, 27, ended an 11-year wait for a first Grand Slam title at last year's Australian Open and followed that success by beating Justine Henin to take the title at the only grass-court major.

"I always like to think that I have few things here and there to improve," said the Frenchwoman, "little bit on the serve still, although it was much better than the first couple matches."

"But overall I thought I played some good match, really going-forward kind of tennis. And that's what has been working well for me here. So I'll just keep going."

On Court one, Sharapova squandered two match points before securing victory just as heavy rain set in at SW19 once more.

The Florida-based Russian took control of her match in the fifth game, when she ended a string of deuces on Sugiyama's serve with successive winners from a lob and a forehand.

Sugiyama broke the second seed's serve in the opening game of the second set before Sharapova hit back to level at 3-3. As rain started to fall, the umpire rejected Sugiyama's calls for play to be halted and Sharapova sealed the match with a forehand winner on her third match point.

"My serve worked really well," Sharapova told reporters after getting 81 percent of her first serves in today, "there's so much room for improvement physically for me. I also need to raise my intensity level."

On the outside courts, three-time Wimbledon champion Venus Williams was locked in a tough battle with Akiko Morigami when the rain came. She took the first set 6-2 but then went into meltdown and was a double break down at 4-1 when the players came off.

Russian seeds Svetlana Kuznetsova, Nadia Petrova and Elena Dementieva were all a set to the good, while it was a similar story for teenagers Nicole Vaidisova and Ana Ivanovic.

In the only men's match to start, Tomas Berdych had taken the first set 6-4 against Hyung-Taik Lee, with the South Korean leading 3-2 in the second which remains on serve.

Despite the weather problems, the All England Club have ruled out the possibility of play on middle Sunday as chief executive Ian Ritchie said the tournament was still sufficiently on schedule.

Only three matches were finished on Saturday and the other was a first-round all-Briton mixed doubles clash in which James Auckland/ Claire Curran beat Lee Childs/Katie O'Brien 6-2, 6-1.

But many, including Williams and fifth-seeded Russian Svetlana Kuznetsova, had to wait 48 hours for their matches to be resumed on Monday.

France's Amelie Mauresmo gestures after winning her singles match against Italy's Mara Santangelo at the Wimbledon tennis championships in London, June 30, 2007. (Xinhua Photo)