Tommy Haas said it was time his tennis peers named names after an unidentified German player accused another of match-fixing during a television interview.
Talk of match-fixing has swirled around tennis for weeks, with the latest accusation by the unnamed German, whose voice was electronically distorted, telling WDR television he was approached by another to place a five-figure bet for him.
The man also said more money could be earned by players through bets than winning matches.
Some German tennis officials and players, including 11-year pro Haas, were skeptical toward Sunday's interview, however.
"It's time people start naming names. Every day someone says something: Andy Murray, Werner Eschauer, Michael Llodra, Arnaud Clement, now someone anonymous. I'm telling them, be concrete -- then we can undertake something concrete. All this talk isn't bringing us further," Haas said.
"There aren't many involved, but its always the same players," the unnamed German said in the TV interview.
"Those that do it are more professional about it than about playing tennis itself," he said.
The man added that individual games and serves could even be manipulated.
"You can't prove that someone lost intentionally. Someone that is involved, or was involved, has to name names," he said. "Threats from the ATP is a blind alley."
The player also claimed to have witnessed "forbidden" betting inside the players' lounge at tournaments.
Two months ago, Belgian player Gilles Elseneer said he was offered -- and turned down -- more than US$100,000 to lose a first-round match against Potito Starace at Wimbledon in 2005.
Clement said last week he turned down money as well, but didn't elaborate.