Graeme McDowell reckons Shane Lowry is in for a shock when he makes his pro debut in this week’s European Open.

The chunky Offaly rookie, 22, stunned world golf when he snatched a fairy tale win in the 3 Irish Open nine days ago.

Shane LowryBut Horizon stablemate McDowell believes the Clara champion should brace himself for a torrid debut in the “cut-throat” pro game at The London Club.

McDowell said: “These guys are good out here and that’s going to be the shock. He rang rings around them last week there in Baltray but it's back to reality a little bit this week as he is really starting from scratch.

“It really depends how he deals with all mentally. It’s a big change, a big step and he’s into the pro world now. It’s a cut-throat world.”

Dealing with his own high expectations will be Lowry’s first test but McDowell also believes the former amateur ace must be careful not to burn himself out.

The Ulsterman was just 23 when he won his maiden European Tour title on only his fourth start in the 2002 Scandinavian Masters but triumphed just once more in the next five years as he struggled to find the right balance in his schedule.

He warned: “Scheduling, long weeks and playing too much golf take a lot of dealing with. It’s going to be a big step for him.

“I will be there if he needs anything.  He only has to ask me questions and if he needs any help. But he’s a big boy and he looks like he can handle himself pretty well."

Asked if he would take burly Lowry under his wing, McDowell joked: “I am not sure if my wing is big enough. He can just about take me under his wing.

“But like I’ve said, I don’t actually know him that well and I am looking forward to meeting him and chat to him. His golf game looks fantastic and it looks good enough to survive out here.

“But it’s a big step-up playing a 30-week schedule.  These boys are good out here. They are very efficiently managed. They don’t make mistakes like Shane would be used to seeing in the amateur ranks.

“My advice to him would be not to follow the crowd.  Do his own thing.  Stick with his own coach and don’t go changing things just because he’s in pro ranks now.”

McDowell has been struggling with a leg injury for the past two weeks but with a stress fracture ruled out, he feels fit enough to tee it up at The London Club after a 13th place finish at Wentworth boosted him from 51st to 47th in the latest world rankings.

Ten Irishmen will be in action with McDowell and Lowry joined by a red-hot Rory McIlroy, Paul McGinley, Damien McGrane, Darren Clarke, Peter Lawrie, Michael Hoey, Gary Murphy and Gareth Maybin.

McIlroy had a chance to challenge for the BMW PGA following his third round 65 but finished fifth in the end to leap four places to 16th in the latest world rankings and third in the Race to Dubai behind new world No 3 Paul Casey and Aussie Geoff Ogilvy.

The Ulsterman, 20, has earned €1.14 million in Europe so far this term but hopes to boost that by taking the €500,000 top prize this week.

McIlroy said: "I feel I've got the game to go and win there. Hopefully, this is a good building block for the rest of the season."

Padraig Harrington remained eighth in the rankings and will return to action for The Memorial in the US next week before putting the final touches to his US Open preparations at the St Jude Classic in Memphis before heading to Bethpage in New York.