World number one Novak Djokovic produced a clinical performance to oust an impressive Nikolay Davydenko from the US Open third round in straight sets.

Djokovic won 6-3 6-4 6-2 on Flushing Meadows' Arthur Ashe Stadium with his Russian opponent unable to penetrate his solid defensive shield.

Serbian Djokovic has twice been a runner-up in New York but is looking in good nick to build a successful campaign for this year's crown after victories at the Australian Open and Wimbledon.

Davydenko, a former top-10 player, is No.39 in the world and now 30 years of age. He looked back to his best form with an array of groundstrokes, but 32 unforced errors to the 22 of Djokovic undermined his chances of an upset.

Those were born of his rival's unquenchable appetite for defensive work, forcing the Russian to attack harder and harder in order to get the winners he needed.

He was only able to win two break points in the match, which may come as a surprise to those who watched it - he went toe-to-toe with Djokovic almost constantly - and convert one.

The 2007 and 2010 finalist, meanwhile, capitalised on five of the 12 he earned - breaking both before and after Davydenko's sole break in the opening set then once in the second and twice in the third when he was all-but defeated.

The Serb has a 60-2 win-loss record in 2011 after the two-hour, seven-minute match.

Djokovic said he was inspired to show off some dance steps after the match in celebration after seeing the wild gyrations of a fan in the stands pictured on the stadium's big screen during one of the changeovers.

"The New York crowd, especially in the night matches, is very special," he said. "You know, they really get involved. They have a lot of fun. They're very loud. A lot of music in the changeovers.

"I think every Grand Slam has something special about it. You know, Wimbledon is very quiet, all white. Here it's all about entertainment."

Djokovic did not give himself good reviews on the first act of his performance against Davydenko.

"I had some ups and downs in my match," he said. "Look, it's the first test I think I had this tournament."

The Serb said he did not underestimate the Russian.

"I was aware of his qualities. You know, Davydenko is a great player," said Djokovic. "He's been around for many years. He knows how to play on this stadium. He knows how to play majors.

"He went out there and played his game, very aggressive. I think I was a little too defensive at the start. But when I needed to adjust, I did. I made the crucial breaks each set."

The 22nd seed Alexandr Dolgopolov is next up for Djokovic after the Ukrainian triumphed 6-7(4) 6-2 6-4 over 6'10" Ivo Karlovic.

Five-times champion Roger Federer fought past Croatia's Marin Cilic 6-3 4-6 6-4 6-2 to book his place in the fourth round.

After what seemed like a fairly regulation first-set win for Federer, Cilic showed why he was once ranked as high as ninth in the world by producing a consummate second-set performance.

The six-foot-six player, currently ranked at 26, held Federer at bay before breaking the Swiss master with the score at 5-4 to level the match.

Federer was not his usual, unflustered self for quite some time after that, and the pair produced some sparkling tennis as they matched each other shot for shot.

The US Open represents the last opportunity for Federer to avoid ending a calendar year without at least one Grand Slam title for the first time since 2002, and the relief on his face as he secured the break that led to him taking the third set was clear for all watching the Arthur Ashe court to see.

After once again going a set down, Cilic's challenge began to fade, although he still forced some scintillating play from the former world number one even as he was broken twice in the fourth and final set.

"It was a tough match," Federer said after the two-hour, 40-minute affair at on a warm but blustery day. "Coming in I knew it was going to be tricky and I'm happy that I was able to counter his pace and his good play."

The Croat double-faulted to give Federer a 5-4 lead in the third set and never recovered. He had just received a time violation by the umpire prior to his costly error.

"The only thing I'm not happy about is that referees are not consistent," he said. "I'm not saying they were wrong, they should just be more consistent with the other players."

Federer conceded the timing of the violation took him by surprise.

"These time violations come out of nowhere sometimes and then they'll never come back again," he said. "If he was really taking too much time it's correct that you warn a guy but then you should just stay tough and also go to point penalty.

"Marin was playing pretty quick, like I was. It was a tough call."

Federer is currently is tied with Jimmy Connors and Pete Sampras for the most US Open titles since the sport turned professional in 1968.

When asked how he was progressing through the tournament the 30-year-old Swiss said: "I'm on track because I'm in the tournament. That's the most important thing at the end of the day. I seriously don't care how I'm playing. I wish I play my best every single time and feel amazing. That's not reality.

"That's what the beauty is of this game is, trying to find a way when you're not feeling great."

In the last 16, Federer will face Juan Monaco after the Argentine player came from a set down to beat Germany's Tommy Haas.

Haas won a first-set tie-break 7-3, but the veteran soon began to flag and Monaco took full advantage to take the next three sets 6-3 6-2 6-3. It is the first time the 27-year-old has reached the second week at Flushing Meadows for four years.

By advancing to the fourth round, Federer became the fourth player to qualify for the season-ending ATP World Tour Finals in November - but said when he arrived in New York, he first and foremost wanted to leave the city with another title.

"As long as I'm in the tournament I know I have a shot, and that's what it's about right now," he said.

Cilic reflected on Federer's game: "Definitely, his serve keeps him in there all the time. And today he was, in those crucial moments, finding a way to make the game a little more difficult for me to read what he was going to do."

Jo-Wilfried Tsonga triumphed in straight sets 6-3 7-5 6-4 over Fernando Verdasco to set up a meeting with Mardy Fish, who beat giant South African Kevin Anderson, also in straight sets, 6-4 7-6(4) 7-6(3).

Janko Tipsarevic and Juan Carlos Ferrero both reached the fourth round after their respective opponents retired through injury.

Serbia's Tipsarevic reached the fourth round in New York for the first time in his career after Tomas Berdych pulled out of their third-round match in the Louis Armstrong Stadium with a shoulder injury.

Number 20 seed Tipsarevic was 5-0 in the second set, having taken the first 6-4, when Berdych conceded due to a shoulder problem which had evidently been making him struggle since the seventh game.

Tipsarevic, who has now bettered his third-round appearance of a year ago, will face Ferrero in the fourth round. The 2003 champion came past fellow Spaniard Marcel Granollers, who also quit his match in the second set..

Ninth seed Berdych had looked in decent form going into this match off the back of a 7-5 6-0 6-0 win over Italy's Fabio Fognini. The 2010 Wimbledon finalist cruised through his first three service games and threatened his opponent's serve each time.

However, his form took a sudden drop at 3-3, as Tipsarevic hit a stunning backhand winner and a delicious drop shot to endanger Berdych's serve for the first time.

Berdych held that game, but after that things went downhill. His next service game saw a catalogue of poor shots give Tipsarevic the match's first break at deuce, and he served out the set.

Berdych had his trainer out to treat his right shoulder in the break between sets, but it did not improve his showing.

Tipsarevic won five straight games in the second set before Berdych finally gave up the ghost and retired.

Former world number one Ferrero raced to take the first set 6-1 against number 31 seed Granollers.

The 25-year-old had never reached the third round of a Grand Slam before in his career, but he got his game together to some extent in the second set, holding serve three times being broken, and he took his cue to withdraw from the match on Court 17.

Eurosport / Reuters