Champion Roger Federer continued his sure and steady march through the Wimbledon field on Sunday, sweeping aside the challenge of Swede Thomas Johansson to reach the fourth round.

The Swiss top seed was joined by second seed Andy Roddick, who won his battle of the big servers with fellow American Taylor Dent 6-3, 7-6, 7-6. Tim Henman also advanced, riding a wave of popular support past Hicham Arazi 7-6, 6-4, 3-6, 6-2.

In the women's draw, champion and top seed Serena Williams advanced with the minimum of fuss, walloping Spain's Magui Serna 6-4, 6-0.

Jennifer Capriati also flexed her grasscourt muscles to send France's Nathalie Dechy packing with a solid 7-5, 6-1 win and French fourth seed Amelie Mauresmo wasted little time securing her fourth round berth with a 6-1, 6-4 victory over Slovakian Ludmila Cervanova.

Swiss top seed Federer bounced Johansson 6-3, 6-4, 6-3 in their second match on grass in three weeks. Federer also beat him in Halle and has now won all six matches against the 29-year-old and plays Ivo Karlovic next.

"I got a lot of first serves in...I felt very comfortable and started to play really well," Federer said.

"It was a great atmosphere -- I think people were just so pleased to see some tennis," he said of the People's Sunday crowd.

Organisers decided to play on the middle Sunday for only the third time in the history of the tournament after losing two complete days due to rain.

IMPROMPTU PERFORMANCE

Roddick was pleased with his impromptu performance. "I thought I played well today," he smiled. "I thought I lifted my game when I had to... you know, I was forced to. If I hadn't I'd be here in a much worse mood.

"If I would have got busted once it could have been the end of a set so I definitely had to concentrate out there."

Next up for Roddick is Alexander Popp for a place in the quarter-finals.

Henman never looked dominant in beating Arazi and will have to up his game considerably if he is to beat last year's runner-up Mark Philippoussis next. The Australian beat Chile's Fernando Gonzalez.

"He was playing some pretty good tennis out there and made things very difficult for me," the British fifth seed said.

"You can't win the tournament in the first week but you can certainly lose it... I have given myself a chance now going into the second week. I know I have to play better."

Elsewhere, eighth seed Rainer Schuettler struggled to maintain his concentration, shuffling out a 6-4, 6-2, 6-3 victim of American 30th seed Vincent Spadea.

Wayne Ferreira, playing in a record 55th straight Grand Slam tournament, lost 4-6, 6-4, 6-1, 6-4 to Schuettler's fellow German Florian Mayer.

The South African said it had been a shame so few fans turned up to watch his match on court seven.

REALLY DISAPPOINTING

"It was really disappointing there weren't that many people out there," he said. "What can you do about it? That's what the weather's done for us.

"It's not the end of the world. I shouldn't have lost the match. It really wasn't where I was and who was around."

Serena, seeking her third successive singles crown here, started steadily but eventually her power and movement overwhelmed the 53-ranked Serna on Centre Court.

The American was pleased with her performance.

"I was pretty excited by myself," she grinned. "I'm starting to play really well," the 22-year-old said.

"I made it through with all the rain. I am feeling better than last year. I'm feeling good about my game -- I'm looking at the positives."

Croatian Karolina Sprem, conqueror of Venus Williams in the last round, triumphed again by the same 7-6, 7-6 scoreline, this time beating 32nd seed Meghann Shaughnessy.

Afterwards she showed little sympathy towards the umpire axed for a scoring gaffe during that second round match against Venus.

"Bad luck for him," she said.

"We have so many people on the court and they need to know the score, not me. It was really big moment for me, and I didn't think about this."

British umpire Ted Watts made an error in the second set tiebreak of Thursday's match against twice former champion Venus when he awarded Sprem a point when she had faulted on a first serve.

The Croatian went on to inflict on Venus her earliest Wimbledon defeat in seven years.