Davydenko's lawyer said the inquiry had been a "farce"
Nikolay Davydenko has been cleared of any involvement in match-fixing after a year-long investigation by the governing body of men's tennis (ATP).
The ATP investigated suspicious betting patterns surrounding Davydenko's shock defeat by Martin Vassallo Arguello at the Sopot Open in August 2007.
But they found no evidence of wrongdoing by either player.
"The ATP has now exhausted all avenues of enquiry and the investigation is now concluded," said a statement.
"A fundamental role of the ATP is to ensure that men's professional tennis continues to be free of corruption.
"For this reason, the ATP instigated an investigation into the circumstances surrounding the match in Sopot.
"The ATP can confirm that it has concluded its investigation and found no evidence of a violation of its rules by either Mr Arguello or Mr Davydenko or anyone else associated with the match."
Davydenko, 27, cited a foot injury as the reason behind the loss but found himself at the centre of the longest-running inquiry ever held into match-fixing in tennis.
Nearly $7m (£3.5m) was placed in wagers on Betfair as Davydenko retired through injury while 6-2 3-6 1-2 down in the second-round match in Poland.
The amount is 10 times the usual amount for a similar-level match and the online betting company took the unprecedented step of voiding all bets on the match.
Most of the money was on Argentine player Arguello, even after the then world number 87 lost the first set.
Davydenko, the current world number six, has always firmly denied any wrongdoing and expressed confidence he would be cleared.
He said he may have inadvertently tipped off bettors by talking too loudly about his injury to his wife during the tournament.
In March this year, Davydenko's lawyer called the investigation a "farce" and told BBC Sport that "it is a very sad story because Nikolay has been badly damaged by all of this".
ATP investigators spoke to Davydenko, his wife and family members and reviewed telephone records of the Russian, Arguello and members of their support personnel.
However, the ATP claimed that "certain individuals declined the requests".
"After lengthy legal proceedings, the independent Hearing Officer directed those individuals to turn over the requested records to the ATP," the statement continued.
"A number of records were received and examined, however due to the length of the legal proceedings, some of the records were confirmed as having been destroyed by the relevant telephone providers in line with local data protection laws."
Meanwhile, a group of Italian tennis players banned for betting on matches plan to sue the ATP for violation of privacy.
Potito Starace, Daniele Bracciali, Federico Luzzi and Giorgio Galimberti were banned for violating the ATP's anti-corruption rules.
Galimberti told La Gazzetta dello Sport newspaper that the ATP should not have made public certain information.
The quartet also plan to sue the betting agency that gave the ATP the information about their wagers.
A fifth Italian player, Alessio di Mauro, who was banned for nine months for betting in November, is not taking part in the legal action.