Ivanisevic, the runner-up at Wimbledon to Pete Sampras last year and to Andre Agassi in 1992, retired in the first round of the Eurocard Open yesterday after losing the opening four games against Sweden's Magnus Larsson. The operation is overdue, the cartilage in the right knee having nagged since it was torn during a kickabout in Croatia last May.
Surprisingly, Ivanisevic persevered with the problem even though he experienced pain in Australia in January and had to default from the doubles event during the ATP Tour event in Dubai a fortnight ago. "My desire to play was more than to do the operation," he said, adding that he had never had surgery before and was "pretty scared".
Ivanisevic expects to be back on the practice courts within three weeks and intends to resume competition on the clay of Barcelona in April.
Sergi Bruguera, the French Open champion, also has problems. The Spaniard retired during the second set of his first-round match against the Russian Alexander Volkov after feeling twinges from the ligaments in his left knee and will seek medical advice from the doctor at the Barcelona football club.
The Stuttgart tournament has now lost both of last year's finalists, illness causing Stefan Edberg, the defending champion, to withdraw on Monday without hitting a ball. Ivanisevic defeated Edberg in the 1992 final, completing a week during which he delivered 105 aces.
He responded to the sympathetic suggestion that enforced rests can prove beneficial by saying: "The only good thing about this is that I will be able to watch my team play in Split."
The tournament still boasts Germany's former Wimbledon champions, Boris Becker and Michael Stich, who are projected to meet in Saturday's semi- finals, though Becker has come close to being shown the door. He was within one misdemeanour of being disqualified when partnering his compatriot, Carl-Uwe Steeb, in a doubles match against Olivier Delatre and Gary Muller on Tuesday night, having incurred a penalty point for kicking a ball into the crowd and joining spectators in whistling at a linesman.
Becker did not realise until later that disqualification from the doubles would also have meant elimination from the singles. As it is, Becker is only out of the doubles. Delatre and Muller went on to win, 6-3, 6-7, 6-2.
Relieved that he had held his temper in check during the final set, Becker went on to win his opening singles match yesterday, defeating Patrik Kuhnen, a Davis Cup team-mate, 6-3,6-3.