Considering he’d had less than five hours sleep, the new US Open champion was remarkably sharp.

Then again, that’s no great surprise. Half the golfing world knows by now that Graeme McDowell is one of the sharpest guys on tour. But he’s kept that way by his entourage.

McDowell’s posse is not quite like the cast of “Entourage”, the hit series produced by Mark Wahlberg that will feature the man from Portrush in its season-ending episode. A speaking part, no less.

He’s talking about people like manager Conor Ridge, swing coach Pete Cowen, caddie Ken Comboy or mind coaches such as Dr Karl Morris or Dr Bob Rotella.

Sipping a coffee as he sits on the edge of a roaring “fireplace” at the Monterey Plaza Hotel, McDowell touches on all the key people, the key moments and the key thoughts that helped him become the first Irish winner of the US Open title.

Before that there’s still time to reflect on the late night celebrations at Brophy’s Tavern in Carmel, where he was plied with shots until the small hours before being whisked back to the hotel by the man he calls “Jerry Maguire”.

Padraig Harrington and his wife Caroline were in the pub as well as dozens of caddies and other tour regulars who wanted to wish the United States Open champion the best.

At 4.30 am Ridge cleared McDowell’s hotel room of late night revellers and began planning a Monday morning that would have made Bob Geldolf rethink the lyrics of that hit song by the Boomtown Rats.

The room is like a bomb site but McDowell is in no hurry to pack up and dash off to the local airport, where his sponsors Marquis Jet have a private plane fuelled and waiting to take him to Los Angeles for an appearance on the Tonight Show and a cameo role in one of his favourite TV series.

The jet can wait. McDowell is savouring every minute of this win.

But by early afternoon McDowell is on the set of the Tonight Show, laughing it up as he records his interview with Leno in front of a live audience. Teen actress Dakota Fanning is on first. The McDowell comes out casually dressed in jeans and a blue shirt. He’s got the trophy and he cleverly plays up to Leno’s cliched patter about the hard-drinking Irish.

Leno showed McDowell memorable pictures of his Sunday night win and cracked jokes about each one.

Holding up a photo of McDowell kissing the trophy, Leno quipped: “The sad thing is, you are in America now. I understand the trophy is now suing you for sexual harassment.” 

The Tonight Show is an institution - the longest running show in the country - and this is massive exposure for McDowell, who is still a relative unknown in the US despite his stirring performance in last year’s Ryder Cup at Valhalla.

Appearing on the show once hosted by Johnny Carson is a major milestone. But getting a cameo on “Entourage” puts McDowell in the same league as Martin Scorsese, U2 and Bono, Phil Mickelson, Lennox Lewis, Hugh Hefner or Dennis Hopper, 

The “Entourage” producers add some glitz the deal by getting McDowell a police escort from Universal Studios to Beverley Hills to film his cameo.

“We had great crack with the guys from Entourage and profile wise this is fantastic for him,” said his manager Ridge, who landed the gig quite by accident. “One of guys on the production team is a friend of mine. I got him tickets for Pebble and suggested Graeme come on the show.

“They’re fans to Graeme’s and he loves the show. So we had a hilarious time and we brought the US Open trophy along. 

“The cast were all passing the trophy around and they were looking for Graeme’s autograph and he was looking for their autographs. 

“He had a small speaking part and they rehearsed it first and then they went off and shot it and had a great time.”

After the filming, the show’s producers put McDowell up in the luxurious Beverley Hills Hotel and even kept the restaurant open late for him as he didn’t arrive until after nine o’clock.

It’s all new to McDowell, who gambled by changing management companies in 2007 - leaving the established ISM stable of Chubby Chandler and opting for Ridge’s fledgling Horizon Sports Management.

“I certainly thought about that long and hard,” McDowell said.  “But I was very single minded as far as knowing that he was the guy that was going to take me to the next level. I felt like I needed a boost of enthusiasm into my career. I needed a boost of energy and I needed a new direction.”

McDowell calls Ridge his “Jerry Maguire” after the character played by Tom Cruise in the 1996 movie on sports agents.

Maguire’s catch phrase was “Show me the money” but that’s only part of the equation for McDowell, who has already made €8m in tournament earnings since 2002.

Pointing to Ridge, who was fielding calls from radio and TV stations, he said: “You’ve just got to look at him. He’s a pretty energetic kind of guy. He doesn’t ever stop and having some focus and direction in my career has been extremely important  for me the last few years. 

“He is someone who is as focussed on my goals and dreams as I am. I think that has been a big part of the process for me.”

McDowell has known tough times in his career and believes that having a top team has helped him reach the top.

Recalling some nightmare weekends in majors over the years, he said: “I certainly hadn’t lost my way in life but when you are in the wilderness in this game, it can be a bleak, dark place. 

“The tough times are tough. This game gives you no love back. When you want love, it doesn’t give it to you.

“When you hope something’s going to happen, it never does. The second you start believing in yourself, relaxing and letting it happen, it’s amazing what’s around the corner.”

And with that Ridge appeared on the scene, clicking his fingers. The US Open champ had to take a break to go and do a phone interview.

Laughing, McDowell said: “It’s Jerry Maguire, baby. Jerry Maguire.”