Top seed and defending champion Andy Roddick struggled to overcome Hyung-Taik Lee of South Korea 6-3, 3-6, 6-2 in the second round of the San Jose Open on Thursday.
Five-times winner Andre Agassi also overcame some erratic play to beat Denmark's Kenneth Carlsen 7-5, 6-1.
The second-seeded American said it was his intent to keep Carlsen away from the net but it took him a while to execute his strategy.
"You think you should take your chance, but then you regret not waiting a couple of more shots," Agassi said. "As the match went on, I got real patient and waited for my opportunities and felt pretty good."
Agassi's third round opponent will be seventh seed Juergen Melzer of Austria, who beat Delray Beach champion Xavier Malisse 6-3, 6-3.
Roddick looked to be cruising to victory after dominating the first set with his huge first serve and forehand, but Lee upped his game exposing the American's weaker backhand.
The world number three won the match when he passed Lee with a forehand down the line to finish the contest with 17 aces and 35 winners.
"I'm not playing great," said Roddick, who broke a racket in frustration in the third game of the second set. "But I'm through and I'm going to keep battling. A lot of people are under the assumption that it's easy to play well every week and it's not."
Roddick will next face Sweden's Thomas Enqvist who pounded American Robby Ginepri 6-1, 7-5.
Eighth seed Max Mirnyi overcame Kevin Kim of the U.S. 6-1, 7-5 and will play third seed Tommy Haas.
Cyril Saulnier of France beat Tomas Zib of the Czech Republic 6-1, 7-6 and will meet fourth seed Vince Spadea in the next round.
