There have been theories thrown out there as to why Djokovic made his coaching decision, but seven-time major champion John McEnroe offered a pretty hilarious theory this weekend.

John McEnroe has joked that Andy Murray agreed to coach Novak Djokovic so he can discover ways to beat the Serbian. The American teased that Murray would then come out of retirement and use the knowledge to get the better of the 24-time Grand Slam champion in a showdown on the court.

John McEnroe believes Andy Murray could come out of retirement once he's done working with Novak Djokovic at the Australian Open. The tennis legend hung up his racket back in the summer after playing doubles with Dan Evans at the Paris Olympics.