Novak Djokovic made serene progress into the fourth round at Wimbledon with a 6-4, 6-4, 6-4 win over American Mardy Fish Friday.

The Serbian fourth seed, who made a shock exit in round two 12 months ago, seems to be peaking at the right time and barely put a foot wrong in a match lasting just under two hours.

Djokovic, largely ignored so far amid all the hype over a possible Roger Federer-Andy Murray final, fired an unreturnable serve to win the match then threw his wristbands into the crowd.

Being under the radar suited Djokovic perfectly.

"Right now, I feel quite okay that people are not talking about me too often, which gives me a freedom to perform the best tennis I can on the court," he said after extending his record over Fish to 4-0.

Roger Federer lost his first set of the tournament but still managed to conjure a comfortable 6-3, 6-2, 6-7, 6-1 victory over Germany's Philipp Kohlschreiber.

The 27th seed was meant to provide a stern test for Federer after disposing of Novak Djokovic at the French Open last month but the gulf in class was immediate as the Swiss maestro opened up a one-set lead in just 37 minutes.

The second was in the bag 30 minutes later but the German rallied from 2-0 down in the third to take it to a tiebreak which he won with a wonderful angled backhand 7-5.

Federer, five times a champion at Wimbledon, snuffed out the rising threat by racing to a 3-0 lead in the fourth and finally booked a fourth-round berth against French Open finalist Robin Soderling of Sweden with a thunderous forehand winner.

Olympic champion Elena Dementieva brushed aside fellow-Russian Regina Kulikova 6-1, 6-2 to book a place in the fourth round for the sixth time in her career.

The fourth seed, who looks to have one of the best quarters in the draw, broke twice in the opening set before wrapping it up in just 24 minutes before Kulikova, playing her sixth match after a tough qualifying run, improved markedly.

The world number 191 made more of a game of it in the second but Dementieva had too much in her armoury, sealing victory with a scrambled backhand down the line.

She will play Russia's Elena Vesnina, who beat Slovakian 14th seed Dominika Cibulkova 7-5, 4-6, 6-4, for a place in the quarter-finals.

Twice former champion Serena Williams outclassed Italy's Roberta Vinci 6-3, 6-4 to book her place in the fourth round.

The 27-year-old American, seeking to add another Wimbledon crown to the Australian Open she won in January, broke for a 3-1 lead in the opening set against the world number 53 and never looked back.

The second seed breezed through the opening set in 28 minutes and though Vinci had the audacity to break back with a refreshing penchant for serve and volley, Williams completed victory with a crunching ace on Court Two.

She will play Daniela Hantuchova of Slovakia, who beat Japan's Ai Sugiyama 6-4, 6-3, for a place in the quarter-finals.

Nadia Petrova is through to the fourth round at Wimbledon following victory over Gisela Dulko.

The Russian 10th seed was made to work hard for the win because one break was all it took for her Argentine opponent to claim the first set.

Petrova's power game eventually told, though, as she went on to break three times in the final two sets to complete a 3-6, 6-3, 6-4 comeback triumph.

Apart from the thud of ball against strings and the applause of the crowd, silence reigned on Court 18 as Daniela Hantuchova beat doubles partner and best pal Ai Sugiyama to reach the fourth round.

So rarely this week has a women's singles match not been played against a soundtrack of grunts, groans, shrieks and all manner of other noises that it was novel to see the pair compete without offending the ear drums of anybody in the vicinity.

The crowd clearly appreciated it as former world number five Hantuchova found her groove after a slow start to claim a 6-4, 6-3 victory and set up a Monday date with number two seed Serena Williams, who the Slovakian lost to at the same stage in 2007.

Hantuchova, who seems to have been on tour forever despite being just 26, admitted making too much noise was difficult with a sore throat while 33-year-old Sugiyama, the oldest woman left in the singles, said grunting was just a waste of her energy.