Isner joy after A-Rod exit

Big-serving Isner, at 6ft 9ins tall, was always going to be handful for the fifth seed but after Roddick's fifth-set Wimbledon final heartbreak, the momentum appeared to be with the higher-ranked player whose 2003 US Open win made him the last American man to win a grand slam.

Isner won 7-6 (7-3) 6-3 3-6 5-7 7-6 (7-5) in three hours and 51 minutes at Arthur Ashe Stadium and will now play 10th seed Fernando Verdasco of Spain in the fourth round, the Spaniard having beaten Germany's Tommy Haas in five sets.

"I played the match of my life to beat him on that stage and in that setting I had to play my best," Isner said having completed his third win over a top-10 player this year following the defeats of Gael Monfils and Jo-Wilfried Tsonga.

Roddick was understandably downbeat at his exit having come into the final grand slam of the year with such optimism.

"It was a tough one to lose, especially after coming back that way," Roddick said following his earliest loss at the US Open since a first-round exit in 2005.

Roger Federer continued his quest for a sixth consecutive title with a four-set victory over tenacious former champion Lleyton Hewitt.

In a rematch of their 2004 final at Arthur Ashe Stadium, when Federer landed the first of his titles, it took four sets to defeat the 2001 winner, although the world number one had to come from a set down before dispatching the 31st seed and fellow 28-year-old 4-6 6-3 7-5 6-3.

Federer said: "This match was close, it could have gone either way.

"The way I came through I was very happy because I knew that being a set down against Lleyton is always going to be a difficult situation for me to be in."