Newport, Rhode Island, 7 July 2011 | AFP/AAP

Australian Matthew Ebden has continued his good form at the Hall of Fame Tennis Championships in Newport, booking a place in the quarter-finals after a hard-fought win over Matthias Bachinger.

Ebden, the 23-year-old world No.157 came from a set down to beat the 92-ranked German Bachinger 2-6 6-4 6-4 in their second round clash.

The West Australian will play sixth-seeded Olivier Rochus for a spot in the semi-finals after the Belgian beat Nicolas Mahut 6-4 7-6 (7-3).

Top-seeded John Isner also won through to the quarter-finals of the $US500,000 ($A468,911) tournament by beating France’s Arnaud Clement in straight sets.

Isner took the second round match 7-6 (7-4) 6-4 on Wednesday, winning 80 per cent of his first serve points at the grass court ATP tournament.

The 6ft 9in, 26-year-old Isner also used his booming serve to hammer 11 aces.

“When I get off to an early break, that’s when I feel like I’m in control,” he said.

“I feel like I play my best when I’m ahead. It didn’t happen in the first set, but it did in the second.”

Isner seized control when he broke Clement in the seventh game of the second set to take a 4-3 lead after the Frenchman double-faulted.

Isner will next face American compatriot Alex Bogomolov.

In other second-round matches, wildcard Denis Kudla upset second-seeded Grigor Dimitrov, 6-1 6-4 and No.8 seed Tobias Kamke beat Donald Young 7-6 (7-3) 6-4.

Edouard Roger-Vasselin defeated Jimmy Wang 7-5 6-4 and Michael Yani advanced when German star Tommy Haas retired with a lower back injury behind 2-5 in the first.