Graeme McDowell confessed that he’s dizzy with excitement, not altitude sickness, having climbed to the summit of world golf with his dramatic US Open win at Pebble Beach.

As he drank in the plaudits from the 40,000 fans that thronged Adare Manor for the opening day of the JP McManus Invitational Pro-Am, the 30-year old Ulsterman confessed that he’s still buzzing after leaving Tiger Woods, Ernie Els and Phil Mickelson trailing in his wake just two weeks ago.

New Zealander Michael Campbell compared the aftermath of a major win as being fraught with the kind of danger that faces a mountaineer who’s just conquered Everest.

“Nobody teaches you to climb down again,” said Campbell, who won the US Open in 2005 but has since slumped to 795th in the world. “People die coming down. When you make it your goal in life, climbing Everest or winning a major, nothing prepares you for what’s at the other end.”

McDowell is determined not to become just another one-hit wonder and not only is he confident that he has what to takes to add to his major haul, players of the calibre of Padraig Harrington, Rory McIlroy and Paul McGinley put aside their own pressing goals to heap praise on the gusty Portrush native.

“Major No 2?” McDowell mused. “As soon as possible. I’m preparing as well as I possibly can for at St Andrews next week but this doesn’t give me any God-given right to go and win the Open.

“All I can draw from this is the confidence that I know I am good enough to do it when the chips are down on the back nine on Sunday in a major championship. 

“The biggest think I take away from Pebble Beach is confidence. I know my game is in the greatest shape it’s ever been in and while I have a lot of improving to do in all aspects of my game, I can get better and better and better.”

Yesterday, McDowell signed for a three over par 75 before tournament host turned up on the 18th green to present him with a crystal memento to mark his US Open victory.

Minutes later he was reunited with the US Open trophy and immediately made it clear that he plans to compete hard for more silverware in the Barclays Scottish Open this week before chasing his second major win in the Open at St Andrews.

After running through the champagne splashed two-week trip that has taken him from Pebble Beach to LA, London, Portrush, Orlando and Limerick, McDowell confessed that he is almost ready to get back to the business of winning golf tournaments again.

“It feel like about two months ago that I holed that winning putt on the last green at Pebble,” he said. “Hard to believe it was only two weeks yesterday. It’s been a great two weeks and I always said if I won a major that you wouldn’t see me for three months - I would be on a beach in the Bahamas drinking myself stupid. 

“But there is a lot of golf to play this summer and good stuff to look forward to. At some point you have to get the business head back on, so tht process started this morning.”

More than 300 fans cheered McDowell onto the first tee at Adare for the 8am shotgun start and he admitted that he is only beginning to get his head around the fact that he is now a major champion.

“It was amazing out there this morning,” McDowell said. “It was great to get back in a golf environment and try and, not put it behind me, but try to semi-get my head attached if I can.

“Once an hour I have a thought where I still can’t believe it. A reality check. When you achieve a dream - and that’s what it was, an absolute dream - it’s quite a surreal feeling and still feels pretty surreal.”

If the trophy wasn’t proof enough that it wasn’t a dream, McDowell still has hundreds of emails, letters and texts of congratulations to trawl through with notes from the likes British Prime Minister David Cameron and major winners Tony Jacklin and Arnold Palmer waiting for him at home. 

He’s a certainty now to tee it up with Rory McIlroy in the Ryder Cup at Celtic Manor in October, but Harrington admitted that he needs a big summer to make the team through the world rankings and may be forced to skip the first event of the FedEx Cup series to appease Colin Montgomerie with an appearance in the final counting event, the Johnnie Walker Championship at Gleneagles.

“It’s going to be a tough one,” said Harrington (76 yesterday) who is seventh in the World Points List and more than €100,000 behind Luke Donald in the race for five automatic places from the European Points List. “It’s a precarious position to be in. I want to make sure I am automatically qualified and don’t want to put it down to the captain’s choice.”

McIlroy, who shot a level par 72, confessed that he “couldn’t stop crying” as he watched close pal McDowell hug his father on the 18th at Pebble Beach and now firmly believes he can win a major - possibly at St Andrews next week where he has a scoring average of 67.34 in six rounds there as a pro.

“Seeing Graeme win made me realise that winning a major was a lot closer than I thought it was,” McIlroy said. “It definitely made the whole idea of winning a major seem a bit more realistic to me.”

McDowell and McIlroy may one day play under Paul McGinley as a Ryder Cup captain and the Dubliner has now accepted that his chances of making this year’s side are over.

“Even if I won twice between now and the end of the season, I don’t think it would be good enough to make the team,” McGinley conceded. “It’s more than likely I will end up as a vice-captain. You can all read between the lines.”

As for McDowell, McGinley said he wasn’t in the least bit surprised by Ulsterman’s major win having captained him in last year’s Vivendi Trophy in Paris.

Asked what he saw in McDowell, McGinley said: “His spirit.”

Then he added: “There’s 50 guys out there on the range who will hit the ball as good, if not better. But he has a wonderful spirit and an absolutely clinical short game, particularly his putting.  If you are going to win a major, that’s the most important aspect, and particularly at Pebble Beach, as you saw.”