In an unprecedented move on Friday, British online gambling company Betfair voided all bets placed the match, saying the market was not fair.
Betfair said about $7m in bets had been wagered 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.
But Eckhard Oehms, Davydenko's agent, denied the 26-year-old had any connection to the plunge.
"We've go nothing whatsoever to do with that," said Oehms.
"Neither Nikolay nor his coach nor me nor anybody out of our entourage has been involved in this.
"This is a matter that is important to us. We can't have his reputation being spotted by things like this."