Graeme McDowell believes Rory McIlroy could become world No 1 if he learns to dig deep like Padraig Harrington.

The Holywood hotshot admits that he threw in the towel in the 3 Irish Open, but doesn’t plan on changing his flamboyant style when he partners Phil Mickelson in the WGC-Bridgestone Invitational at Firestone.

Targeting a major build up to next week’s US PGA, McIlroy said: “Everyone is different and I know that I can catch myself sometimes losing some interest but for me that is the way I am.

“I go some weeks when I’ve got it and I go some weeks I don’t and I lost a lot of interest over the weekend there at the Irish Open. A lot of interest.

“There is something about the Irish Open and it’s an environment that I don’t really feel comfortable in.

“Everyone wants you to win it almost more than you do. It would be great to win it, but I’ll live if I never win it.”

US Open champion McDowell reckons McIlroy needs to grind like Harrington if he is to become the complete player.

He said: “If you put Padraig Harrington’s X Factor, his stubbornness, into Rory, the guy is No 1 in the world in two years. No doubt about it. The guy is that good.”

McIlroy insisted that motivation won’t be a problem over the next two weeks as he chases his first World Golf Championship and major victories.

After a practice round with Angel Cabrera, McIlroy said: “They’re two huge weeks with a World Golf Championship and a Major so they don’t really get bigger than that.

“It would be nice to have a really good go at it next week in the US PGA but it would be great to have a good go at this one, as well.

“It’s a great draw for me to be playing alongside Phil but I would be very happy winning here and coming second in the PGA.” 

McDowell partners Padraig Harrington for the first two rounds in Akron, where the Dubliner hopes to seal his Ryder Cup place by improving on last season’s runner up finish to Tiger Woods.

Ryder Cup rookie McIlroy is certain that Harrington will get a wildcard from Colin Mongtomerie if he needs one and he’s looking forward to having the Dubliner in the team room.

McIlroy said: “His Ryder Cup record has not been great but just to have him in the team room will be invaluable not just for me and the other rookies like Martin Kaymer but for everyone.”