Pete Sampras believes tennis is free of performance-enhancing drugs now, as well as during his 14-year pro career that ended in 2002.
The winner of 14 Grand Slam titles says other than "a random case here and there" he doesn't see the top players engaging in doping.
All top tennis players are subject to being tested without warning. The admission in January by Lance Armstrong that he used banned substances in all seven of his Tour de France victories has increased the focus on doping in all sports.
"It's just my feeling," Sampras said Monday night after playing doubles with top-ranked Novak Djokovic in the Los Angeles Tennis Challenge exhibition.
"I don't think players are that sophisticated in tennis," he said, referring to the elaborate system Armstrong used to avoid detection. "It's not their culture. I don't think it's in their nature."
Last month, the International Tennis Federation banned 124th-ranked Barbora Zahlavova Strycova of the Czech Republic for six months for doping. She tested positive for the stimulant sibutramine at a tournament last fall. She said the drug got into her system through a supplement and denied taking it to enhance her performance.
"It's a random case here or there," Sampras said. "I don't see the top guys messing around with that. Maybe I'm naive."