With serves touching 150mph and plenty of on-court sass, Shelton announced himself with his run to the New York semi-finals in 2023.
The left-handed American reached another Grand Slam semi-final in Melbourne this year, but came unstuck against Sinner.
His progress at the next two majors was blocked by Alcaraz at Roland Garros and Sinner again at Wimbledon.
“I think the next guy will have to have a huge ego if he wants to be in the mix – so it can be someone like Shelton, maybe,” said Mouratoglou.
“He will have to make progress but I think his confidence in himself and in his game is big enough.”
Former British number one Greg Rusedski agrees Shelton has the “firepower” to win a major.
“But only if he makes the improvements on his backhand, his court positioning and plays the big points better,” Rusedski added.
