LONDON – As the NBA grapples with a betting scandal, tennis must now confront a potential gambling scam of its own.
Officials on Friday 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.
In an unprecedented move, British online gambling company Betfair voided all bets Friday placed on Thursday's second-round match at the Prokom Open in Sopot between the defending champion and No. 4-ranked Davydenko and No. 87-ranked Martin Vassallo Arguello of Argentina.
Betfair said it received about $7 million in bets on the match -- 10 times the usual amount -- and most of the money was on Arguello to win, even after Davydenko won the first set 6-2.
The tennis probe comes in the wake of the scandal involving former NBA referee Tim Donaghy. He is the target of an FBI investigation for allegedly betting on games, including some he officiated, during the last two seasons. He resigned July 9.
"You try to leave it to the players to play the game the right way," said Andy Roddick, ranked fifth in the world. "I think we expect that of them. If something's found that's shady, I, for one, will be extremely (ticked) off.
"Obviously you want to wait and see it play out, but it's too bad that it only takes one idiot to ruin things and create a bad story."
Arguello won the second set 6-3 and was leading 2-1 in the third when the Russian retired. Davydenko said he aggravated a left foot injury in the second set. He received medical attention from a tournament trainer before deciding to quit.
"I don't think that he (Davydenko) has something to do with this," Arguello said Friday. "I was playing against him, but he was playing also with an injury, and that's all that I know about the match, and that's also what I felt in the match. I felt nothing else."
Betfair, which has had an agreement with the ATP since 2003 to share information on any irregular betting activity, said it was concerned with the volume of wagers coming in on Arguello from the start.
"We think the market quite clearly wasn't fair," Betfair managing director Mark Davies said. "The prices seemed very odd. As a result, in the interest of fairness and integrity and in consultation with the ATP, we have decided to void the market and return all stakes to (bettors)."
It's the first time the company has taken such a step in any sport. Davies said Betfair would turn over its betting records for the ATP to investigate.
"The ATP takes issues surrounding gambling extremely seriously," the men's tour said in a statement. "We are committed to ensuring our sport remains corruption free and have strict rules in place governing this area.
"In addition we have memorandums of understanding with U.K. and European betting companies that ensures information pertaining to any ATP Tour match that may look suspicious, based upon gambling patterns, is shared with us immediately."
ATP officials said Friday that Davydenko had left Poland.
"Normally I try to fight to the end but it was very painful and I may have done even more damage by trying to finish the match," Davydenko said Thursday after the match. "Since the beginning of Monday I've had a problem with my left toes. Today that became a problem with my foot."
Since losing in the fourth round at Wimbledon to Marcos Baghdatis, Davydenko lost three straight first-round matches -- to Gael Monfils at the Swiss Open, Florent Serra at the Dutch Open and Gilles Simon at the Croatia Open -- before beating Andrei Pavel, 6-3, 6-4 in the opening round in Poland.
Arguello lost 2-6, 6-4, 6-2 on Friday in the quarterfinals to another Argentine player, Jose Acasuso.
"I saw Davydenko playing very well the first set, and I saw also that he had problems with his feet, and that was true, he was not inventing that, so it's difficult to suspect him," Arguello told The Associated Press by telephone from his hotel room in Sopot.
Fellow Russian Marat Safin, playing this week in Washington, declined to speculate about the Davydenko situation.
"I don't really care," Safin said. "Whatever people do, and whatever they want to do, I don't care. I just want to play my matches and enjoy my time. I've enough problems myself."
At Wimbledon in 2006, Betfair reported irregular patterns surrounding a first-round match between British wild card Richard Bloomfield and Carlos Berlocq of Argentina.
Berlocq, who was ranked 170 places higher than Bloomfield, lost 6-1, 6-2, 6-2. Most of the bets placed were on Berlocq to lose. However, no wrongdoing was detected.
Allegations of match-fixing in tennis have cropped up in the past.
In 2003, bookmakers reportedly suspended betting six hours before Russian player Yevgeny Kafelnikov's match in Lyon, France, against Fernando Vicente after a big wager was place on the Spaniard. Vicente, who had been winless for several months, won in straight sets. There was no suggestion either player was involved in wrongdoing, and no investigation was made by the ATP.
Several Russian tennis players were photographed a few years ago with Alimzhan Tokhtakhounov, a suspected mobster from the former Soviet republic of Uzbekistan who was accused of fixing the pairs and ice dancing events at the 2002 Salt Lake City Olympics.
Photographs of Tokhtakhounov with Kafelnikov, Safin and Andrei Medvedev were taken off Medvedev's Web site in 2002 after the man's arrest. Tokhtakhounov spent nearly a year in a Venice, Italy, prison but escaped extradition to the United States in 2003 on the Olympic rigging charges.
Associated Press writer Ryan Lucas in Warsaw, Poland, contributed to this report.