Novak Djokovic beats Julien Benneteau in US Open third round

Defending champion Novak Djokovic continued his ruthless progress at the US Open with a 6-3 6-2 6-2 third-round win over Julien Benneteau of France.

The Serbian has won each of his three matches in straight sets.

He said: "Usually I don't like to play the first matches [of the day] but it was important for me to start off very strong and I played really well."

Andy Roddick, who will retire after the tournament, beat Fabio Fognini and will face Juan Martin del Potro next.

Del Potro, the 2009 champion, overcame fellow Argentine Leonardo Mayer 6-3 7-5 7-6 (11-9).

Number 20 seed Roddick, the 2003 champion, had to work hard for a 7-5 7-6 (7-1) 4-6 6-4 victory over Fognini.

He later paid tribute to a partisan home crowd at Flushing Meadows.

"I'd be an idiot not to use the crowd right now; it's a huge advantage," he said. "Each match is almost like it's another memory."

Benneteau, the 31st seed, almost beat Roger Federer at Wimbledon this year, but rarely troubled Djokovic on Arthur Ashe Stadium.

The Frenchman could not live with Djokovic's power and precision from the back of the court as the second seed won in an hour and 37 minutes.

Djokovic will face the Swiss 18th seed Stanislas Wawrinka, a 6-4 6-4 6-2 winner over 14th seed Alexandr Dolgopolov of Ukraine, in the fourth round.

Number four seed David Ferrer of Spain beat Lleyton Hewitt 7-6 (11-9) 4-6 6-3 6-0 to set up a last-16 clash with France's Richard Gasquet.

Australian Hewitt, the 2001 US Open champion, had five set points in the first set against Ferrer but could not take them and lost 11-9 in a tie-break.

The Australian came back to win the second set before running out of steam.

Gasquet, seeded 13th, ended the run of American wildcard Steve Johnson with a 7-6 (7-4) 6-2 6-3 victory.

Johnson's compatriot John Isner, seeded ninth, lost in a late-night thriller, as Germany's number 19 seed Philipp Kohlschreiber won the fifth set to claim a 6-4 3-6 4-6 6-3 6-4 win.

Kohlschreiber will face Serbia's number eight seed Janko Tipsarevic, who beat Slovenian Grega Zemlja 6-4 6-3 7-5.

In the men's doubles third round, British pair Colin Fleming and Ross Hutchins were beaten 6-3 6-4 by American brothers Christian and Ryan Harrison.

But Fleming returned to the court with mixed doubles partner Sania Mirza of India to progress with a 6-4 7-6 (9-7) win over Americans Melanie Oudin and Jack Sock in the second round.

Britain's Josh Ward-Hibbert beat South Korea's Kang Ku Keon 6-2 6-4 in the first round of the boys' singles, but Luke Bambridge lost 6-3 6-4 to Harrison Adams of the United States.