Few sports over the last year have been rocked harder by "gambling" controversies than tennis.

It was just over a year ago that officials confirmed they were investigating suspicious betting patterns on a match involving top-seeded Nikolay Davydenko of Russia, who retired with an injury against a low-ranked opponent at an ATP tournament in Poland.

Although Davydenko had suffered three first-round defeats in his last three tournaments, was injured in an earlier-round match, and showed signs of injury in the second set, it did not make sense to Betfair that such a heavy betting volume would go in Arguello's direction at that point of time in the match, an Associated Press report concluded.

Per its agreement with the ATP, the European betting exchange Betfair notified the Tour of what it deemed "suspicious behavior" and it has since been revealed that nine people based in Russia had bet US$1.5m on Davydenko losing while two unknown people would gain US$6m from the loss.

And while $7 million was bet on the match (10 times the usual amount), on September 11, 2008 Davydenko was cleared of any involvement in match-fixing. And now comes word that the US Tennis Open ensured their event was not open to online gambling by players and/or others. 

"We didn't want people at the event to have access to gambling sites," Larry Bonfante, CIO of the U.S. Tennis Association (USTA), told US Today.

Bonfante is proud the sport is considered "above board" and "squeaky clean," and filtering out access to gambling sites is a proactive step taken to head off any trouble, he said.  The action followed the Davydenko match scandal and rumblings that another tennis player was allegedly going to "throw a match". 

Officials point out that some 17,000 attempts were made during this year's US Open to access online gambling websites.

"What the rationale there was for all this, we don't know," Bonfante says.