Three of the last four major finals have been contested between Djokovic and Murray and they have established themselves as the top two players in the world ahead of Roger Federer and Rafael Nadal.
The Serb will remain top of the rankings after Murray missed the French Open, but Petchey says the British player could claim the world number one spot before the end of the year.
"I think he's got a great shot," he added.
"Obviously it was disappointing for him to miss the French Open. There's a lot of ranking points on offer there and clearly that was something that got Novak ahead of him right now.
"But it's definitely the Novak and Andy rivalry right now. Rafa's in the mix at the moment, as is Roger, but those two - in terms of the major finals that they've played at New York, Australia and now here at Wimbledon are certainly going to be vying for number one by the end of the year.
"It's going to be fantastic to see that race and it'd be another tick in the resume if Andy can get there.
"You wouldn't bet against it."
