Former Open champion Gary Player believes that winning the US Open will be the toughest tournament for Phil Mickelson to keep hold of.
The American pro clinched the Claret Jug at Muirfield on Sunday by three shots, adding all the Major titles to his achievements apart from the US Open.
"That is going to be the biggest challenge of all the majors for him," Player told BBC Radio Five Live. "Because he is not a good driver and when you play the US Open you will have to use your driver.
"This is a monumental task for him but he has got that thing called it, which the majority of people don't have. I think he will probably win it. You can't describe it. It is a gift that is loaned to you from the man above."
British pro Justin Rose clinched the US Open this year.