KEY BISCAYNE, Fla. -- Goran Ivanisevic's shoulder hurt so much Saturday that he quit while he was ahead, and the chronic injury could keep him from defending his Wimbledon title in June.

The latest flare-up in Ivanisevic's torn left rotator cuff forced him to retire leading Franco Squillari 4-3 in his opening match at the Nasdaq-100 Open.

Ivanisevic wants to delay surgery because it would sideline him for six months and force him to miss Wimbledon. Instead, he said, he'll likely take a couple of months off and hope rest helps.

That may mean skipping Croatia's Davis Cup match next month at Argentina, and perhaps the entire clay court season, including the French Open.

"If I take whole clay off and I come to Wimbledon and then is same pain, then I will hang myself probably somewhere in London," Ivanisevic said. "I want to play Wimbledon. That's my priority."

Ivanisevic's shoulder bothered him in 2001, when he made an improbable run to the Wimbledon title as a wild card. This year the injury has gotten progressively worse, and he has lost seven of 13 matches.

Saturday's match was the first for Ivanisevic since Feb. 25.

"This amount of pain is just more and more, which I cannot handle," he said. "This is just killing me. I want to play, and I can't play."

Three-time champion Pete Sampras served himself out of trouble in the final match of the second round, smacking 18 aces to beat Jarkko Nieminen 4-6, 6-3, 6-2.

Also, top-seeded Lleyton Hewitt edged Paradorn Srichaphan 7-6 (3), 7-5. Hewitt's next opponent will be No. 27 Jan-Michael Gambill, who advanced by beating qualifier Andre Sa 7-5, 6-3.

No. 6 Marat Safin looked strong beating Mark Philippoussis 7-6 (4), 6-1.

"For first day, it was beautiful," the big Russian said. "I hope I can play this way next matches."

No. 8 Thomas Johansson, an upset winner over Safin in the Australian Open final, eliminated Arnaud Clement 6-3, 6-4. Davide Sanguinetti, who has won two tournaments this year, retired with a headache and dizziness trailing No. 15 Guillermo Canas 6-4, 3-1.