Reigning Australian Open champion Novak Djokovic is unsure whether gambling advertisements should have taken their place at the grand slam.
Melbourne Park's biggest venues - Rod Laver Arena, Hisense Arena and Margaret Court Arena - have screens advertising a major betting company on rotation.
It's the first time gambling organisations have been able to advertise to those visiting the Open.
After visiting Rod Laver Arena to dispatch Korean Hyeon Chung and take his place in the tournament's second round, Djokovic questioned the sport's relationship with the gambling industry.
"It's a fine line. It's on a borderline, I would say," he said.
"Whether you want to have betting companies involved in the big tournaments in our sport or not, it's hard to say what's right and what's wrong."
That betting advertisements have only been allowed this year shows that tennis has been slow to embrace the lucrative sports advertising dollar.
But on a day when accusations of match-fixing were circling after a sensational BBC-BuzzFeed report, the advertising seemed like an unwelcome addition to the tournament.
Djokovic said he could see both sides of the argument.
"There is also many betting companies that on the websites are using the names, the brands, images of tournaments and players and matches in order to profit from that," said the world No.1.
"Tennis hasn't been really getting the piece of that cake.
"I think it is a subject (worthy) of discussion."
Influential independent Senator Nick Xenophon said the proliferation of advertising and match-fixing was linked.
"This goes to a broader issue about gambling, sponsorship and tennis authorities effectively and sporting authorities and sporting codes being hooked on gambling revenue themselves," he said.
"We have seen the revelations today that some players are being offered something like US $50,000 by international betting syndicates to play a little differently, to fix the outcome of a game because there is so much money riding on it."
