Hewitt rallied to beat Arnaud Clement of France, 6-7 (5-7), 6-4, 7-6 (8-6) in a match that lasted three hours and 36 minutes, one day after the top-seeded Australian beat German wild card Markus Hantschk in three sets in the first round.
"I think I was still feeling the effects of that (first round) match," Hewitt said.
Hewitt broke Clement's serve to force the decisive third set tiebreak. Clement took a 5-3 lead in the tiebreak, but Hewitt came back again, winning the next three points. Holding a 6-5 lead, Hewitt hit a wide forehand on match point.
But Hewitt cashed in his second match point when Clement retrieved a deep forehand down the line and returned it long.
"Yeah, I'm trying to practice for five-setters to better prepare for the French Open," Hewitt joked after the match. "I'm not playing my best tennis but I'm battling out there. Another great match today and I made some big points."
After losing the first set in a tiebreak, Hewitt won the first five games of the second set and dropped the next four before serving out the set.
Clement led 3-1 in the third, but Hewitt broke back and evened the match. The Frenchman converted his second break point to go ahead in the ninth game of the second set, but Hewitt again broke back to force the tiebreak.
The world No. 1, Hewitt is competing in his first ATP tournament since March 21, when he was upset by Francisco Clavet in the second round of the NASDAQ-100 Open in Miami.
While Hewitt was able to avoid the upset, the fourth-seeded Roddick was not as fortunate as he endured a 3-6, 6-2, 6-3 loss to Agustin Calleri of Argentina.
Roddick was not alone among top players that were ousted as second-seeded Spaniard Carlos Moya was the biggest upset victim of the day.
Moya suffered a 7-5, 6-4 defeat to 16-year-old Spanish teen-ager Rafael Nadal, who recovered from a break down in both sets to beat his idol.
"The truth is I feel bad for him," Nadal said. "I played very well tonight but he was nervous and not at his best. I could see that and I felt so bad at one stage that I did not think I could continue. I did not celebrate the win as I normally do.
He's the best player I've ever beaten."
"I'm not disappointed I lost to him, I'm disappointed about the way I played today," Moya said. "I know it's not the last time I'm going to lose to him but I'm disappointed in the way I played."
Unlike the top two seeds, defending champion and No. 3 Roger Federer of Switzerland cruised into the next round with an easy 6-1, 6-1 rout of Armenian qualifier Sargis Sargsian.
Eighth seed David Nalbandian of Argentina and No. 9 Rainer Schuettler of Germany were able to move on. Nalbandian posted a 5-7, 6-2, 6-3 victory over Frenchman Anthony Dupuis, while Schuettler advanced with a 6-4, 4-6, 6-4 victory over countryman Lars Burgsmuller.
Mariano Zabaleta sent another seed packing with a 3-6, 6-3, 6-1 victory over No. 14 Tommy Robredo of Spain.
In matchups of unseeded players, South African Wayne Ferreira rolled to a 6-1, 6-2 victory over Spaniard Feliciano Lopez; Mikhail Youzhny of Russia bested Karol Beck of Slovakia, 6-7 (7-9), 6-4, 6-2; Gaston Gaudio of Argentina outlasted Spaniard David Sanchez, 6-7 (8-10), 6-3, 6-1; and Mark Philippoussis of Australia defeated Xavier Malisse of Belgium, 6-3, 7-6 (7-5).