Roddick and Djokovic march on at US Open

 ANDY Roddick continued his impressive start to his US Open campaign with another emphatic straight sets victory over France's Marc Giquel.

 EASY PROGRESS: Andy Roddick wastes no time in booking his place in round three at Flushing Meadows

The 2003 champion finished after midnight for the second successive match on the Arthur Ashe Stadium, cruising to a 6-1, 6-4, 6-4 victory.

The 2009 Wimbledon finalist will now face compatriot John Isner, who will tower above Roddick, standing at a mammoth 6 ft 9ins.

"John has been on good form of late and it's going to be a completely different match," said fifth seed Roddick.

"He's a big server and it's going to come down to a few points here and there, I won't be able to break as often as I could today.

"Marc started to come back a lot stronger today so I was glad to be able to pull it out."

Meanwhile, fourth seed Novak Djokovic also advanced without breaking sweat at Flushing Meadows, easing past Carsten Ball to take his place in the last 16.

The 22-year-old Serb raced to a 6-3, 6-4, 6-4 victory to set up a clash with American qualifier Jesse Witten.

"I feel great and I feel ready, "said Djokovic. "I'm confident on the court and I feel more focused and I have a big desire to perform and win the matches."

Elsewhere, American 21st seed James Blake sealed a hard-fought win over 6-4, 3-6, 7-6, (8-6) 6-3 win over Olivier Rochus while Russia's Nikolay Davydenko swept aside Jan Hernych 6-4, 6-1, 6-2.

And Spaniard Fernando Verdasco, seeded tenth, cruised past Florent Serra 6-3, 6-0, 6-3 to book a clash with Germany's Tommy Haas.