MELBOURNE, Australia — Novak Djokovic recalled his own brush with match-fixing, as the start of the year’s first Grand Slam tournament was overshadowed by corruption allegations.

Djokovic started his bid for a sixth Australian Open title with a 6-3, 6-2, 6-4 win over Chung Hyeon of South Korea on Monday, hours after the BBC and Buzzfeed News published reports alleging match-fixing had gone unchecked in tennis.

No players were identified in the reports, which alleged 16 players had been flagged repeatedly with tennis authorities but not sanctioned on suspicion of match fixing. Half of those are entered in the Australian Open, the reports said.

The governing bodies for the sport, and the Tennis Integrity Unit, issued a joint statement, read by ATP chairman Chris Kermode at a hastily-convened news conference at Melbourne Park.

Kermode said tennis authorities “absolutely reject any suggestion that evidence of match-fixing has been suppressed for any reason, or isn’t being investigated.”

Djokovic later responded to a question about an approach ahead of a tournament in St. Petersburg, Russia, in 2007.

“I was approached through people that were working with me at that time, that were with my team,” he said. “Of course, we threw it (the approach) away right away. It didn’t even get to me. The guy that was trying to talk to me, he didn’t even get to me directly. There was nothing out of it.”

Serena Williams was on court preparing for her opening 6-4, 7-5 win over No. 34-ranked Camila Giorgi when Kermode was holding a news conference to respond to the fixing allegations.

Like Djokovic, Williams won three of the four major titles last season, but hadn’t finished a competitive match for months.