Djokovic, Roddick show US Open threat

Novak Djokovic and Andy Roddick signalled the strength of their challenges for the U.S. Open title by breezing into the third round with comfortable victories Thursday.

Djokovic, a runner-up in 2007, beat Australia's Carsten Ball 6-3, 6-4, 6-4 while Roddick cruised past France's Marc Gicquel 6-1, 6-4, 6-4. Both will face American opponents in round three: Serbia's Djokovic against No.276-ranked Jesse Witten and Roddick against big-serving compatriot Jon Isner.

There's a lot more against John that's out of my hands," Roddick said. "I know he's going to come out and just play super, super aggressive," Roddick said. "I'm just going to have …