World No. 21 Fabio Fognini believes it would be “very difficult” for Roger Federer to win another Grand Slam title in the 2016 season unless world No. 1 Novak Djokovic is “having a bad day.”

In an interview with Feder Tennis, Fognini opened about Federer’s chances of an 18th Grand Slam in the upcoming season. Fognini is convinced that Djokovic’s “incredible continuity” into the next year would be hard to beat. However, the Italian tennis pro admitted the Swiss Maestro is the only one who could take down the Serb in a tennis match.

“Numbers and statistics do not serve him [Federer], but he is an amazing champion that made the history of tennis,” Fognini said, reports Tennis World USA. “Sincerely I hardly say that he has no chances, but against a Djokovic like this Roger has to play at his best and hope that the Serb is having a bad day.”

Federer has defeated Djokovic this season in a final round match-up at the Cincinnati Masters. However, the 17-time Grand Slam winner has never topped “Djoker” in other major title tournaments like the Wimbledon, US Open, and most recently at the ATP World Tour Finals in London.

Federer will head into the 2016 season with a new coach in Ivan Ljubicic after parting ways with his childhood idol Stefan Edberg. The world No. 3 will have a chance to become the first $100 million man in the tennis world if he wins the Australian Open in January next year at Melbourne Park.

According to Tennis News, Federer has earned a total of $97.3 million through the end of the 2015 season, while Djokovic is close behind with $94 million in career prize packets. The Australian Open will have a prize money of $3.85 million for the winner, and with a victory at the first Grand Slam event of the year, Federer could break the $100m barrier.