SAN JOSE, California (Reuters) - Andy Roddick brushed off a second set fightback by Ryler DeHeart to defeat the qualifier 6-1 7-6 and advance to the second round of the San Jose Open on Wednesday.

Roddick, the world number seven, breezed through the first set but was broken early to trail 3-0 in the second.

Fellow American DeHeart served for the set at 5-3 but could not close it out as the big-serving Roddick fought back to force a tie-breaker, then sealed it 7-1 with a forehand winner.

Playing in his first match since his Australian Open quarter-final defeat, Roddick finished with 11 aces and will next meet Leonardo Mayer in the second round.

Earlier, Czech Radek Stepanek became the first defending champion to lose in the tournament's first round in 20 years when he was ousted by Belgian Xavier Malisse 6-3 6-4.

German fourth seed Tommy Haas was also eliminated, falling 7-6 6-2 to Uzbekistan's Denis Istomin in the second round of the $531,000 hardcourt tournament.

Another seed, Fernando Verdasco of Spain, had to battle hard to avoid joining Stepanek and Haas on the way home but the second-seed prevailed over Lu Yen-hsun 6-3 6-7 6-3 in the last match of the day.

Third seed Stepanek had four break points against Malisse, but it was the Belgian who made the most of his chances, breaking once in each set to upset the world number 14.

"I've been injured for a while, so this time I had no pressure on me ... There was nothing to lose."

The victory was the former top 20 player's first on tour since June.

Haas failed to convert five break point chances in the opening set against Istomin, who will play sixth seed Philipp Kohlschreiber in the quarter-finals after the German thrashed Israel's Dudi Sela 6-2 6-0.

Czech fifth seed Tomas Berdych also made the quarter-finals, posting a 6-3 6-2 victory over Finland's Jarkko Nieminen.

(Reporting by Gene Cherry and Jahmal Corner; Editing by Ian Ransom and Patrick Johnston; To query or comment on this story email sportsfeedback@thomsonreuters.com)