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.

All eyes will be on Andy Murray and Novak Djokovic over the next fortnight at the Australian Open as the Scot sets his former rival a new challenge, having crowned him tennis' 'GOAT'