Newport, Rhode Island , 6 July 2011 | AAP

Australian Matthew Ebden has recorded an upset victory over No.4 seed Ryan Sweeting from the United States in the opening round of the Hall of Fame Tennis Championships.

Ebden, the 23-year-old world No.157, beat Sweeting 6-4 6-2 in the grasscourt event.

In other action, John Isner and Nicolas Mahut, who played the longest tennis match in history last year at Wimbledon, both cruised to victories.

Top-seeded American Isner needed just 63 minutes to beat Slovakia’s Karol Beck 6-3 6-2 on Tuesday.

Frenchman Mahut dominated Argentina’s Sebastian Decoud 6-1 6-0 in 51 minutes.

“It’s something we’re not used to,” Isner joked of the quick matches.

“The points actually aren’t grinding like hard court or clay. It’s good to go out there and get a real good sweat. Any match that’s this quick is good, especially the first round.”

Isner outlasted Mahut in 11 hours, five minutes last year at Wimbledon.

They met again last month with Isner winning in three sets in a match that lasted about two hours.

“If we play each (here) it’s in the final, then we’d both be happy,” Mahut said.

In other first-round action, American wildcard Denis Kudla survived 24 aces against him to beat big Croatian Ivo Karlovic 7-6 (7-4) 4-6 6-4 and Taiwanese qualifier Jimmy Wang upset third-seeded Russian Igor Kunitsyn 4-6 7-5 6-2.

Tommy Haas got past fellow German and No.7 seed Michael Berrer 7-6 (11-9) 6-4 and Frenchman Arnaud Clement beat American Ryan Harrison 6-4 6-1.