Players involved in a mixed doubles match at the Australian Open say they were interviewed by the Tennis Integrity Unit (TIU) after newspaper reports of suspicious betting patterns.
The New York Times said an online bookmaker suspended betting as Lukasz Kubot and Andrea Hlavackova beat David Marrero and Lara Arruabarrena 6-0 6-3.
Most of the money was placed on Spain's Marrero and Arruabarrena to lose.
All four players rejected the possibility of match-fixing.
In an interview with the Times, Marrero blamed a knee injury for the pair's poor display.
Online bookmaker Pinnacle suspended betting before the match and notified local police.
However, rival bookmakers William Hill, a sponsor of the Australian Open, says it saw no suspicious betting activity on the match. Betfair said it also kept betting open.
Poland's Kubot, 33, Czech partner Hlavackova, 29, said they had never been approached by the TIU before and said they were unaware of anything unusual or irregular about the match.
"It's not very comfortable to think we didn't win the match on our terms," said Hlavackova. "We played our best, we did very well and we won."
Governing body Tennis Australia declined to comment on the case.
Tennis has been under intense scrutiny in the wake of reports published by the BBC and BuzzFeed News that claimed authorities had ignored widespread evidence of match-fixing involving 16 players ranked in the top 50 over the past decade.
In a separate, unrelated case, former top-200 tennis player Nick Lindahl pleaded guilty in a Sydney court to a match-fixing charge.
Prosecutors claimed the Australian told two people he would intentionally lose a match at a lower-tier event in 2013 so they could bet against him.