By Larry Fine

BETHESDA, Maryland (Reuters) - While some golfers might feel added pressure in defending a major championship, Graeme McDowell said he felt liberated by giving back the U.S. Open trophy he won last year at Pebble Beach.

"It's tough to look forward when all everyone wants to talk about is the past," the Northern Irishman told reporters on Tuesday, two days before the 111th U.S. Open gets underway at Congressional Country Club.

"I felt different yesterday on the golf course. I really felt like a weight had been lifted off my shoulders already, and I'm excited about the week."

"It's been a special 12 months," he added about all the attention he received. "I'm here now, happy to give the trophy back and excited to move on with the rest of my career.

"I'm level par Thursday morning the same as everyone else. I'm just one of the guys trying to win it back."

Separating him from most others in the 156-man field is the confidence that comes from already knowing he has what it takes to win a U.S. Open.

"I'm here at a U.S. Open for the first time believing in myself that I can win on a U.S. Open setup because I did it last year," he said. "I really have a strange feeling this week."

The seventh-ranked McDowell, understandably, suffered a letdown after his brilliant run last year.

"The last three or four months has been difficult," he said. "Sometimes a run of momentum and adrenaline sort of has to hit a brick wall, and I guess I hit my brick wall. I've been trying to get over that wall ever since."

McDowell has yet to win in 2011 and he has missed three cuts in his last five U.S. Tour events. He also missed the cut at the European PGA Championship last month and shot a third-round 81 at the Wales Open to wreck his chances.

"At some point, those kind of runs inevitably have to come to an end," he said. "I have no regrets about the last 12 months. I've enjoyed every second of it. Yeah, I've hit a rough patch here the last three months but I've really felt my game coming around the last four or five weeks."

McDowell doubts he will ever again experience the emotional highs of last year, but is convinced he can improve and accomplish a lot more in golf.

"Can I ever top 2010? I probably can't top the way it felt to win my first major championship, to hole the winning putt at the Ryder Cup ... to win two or three other times outside of that.

"I can really up my level of consistency," he said, pointing out that his 2010 successes came in bursts. "I want to win more major championships of course and I want to win more events all over the world.

"I know how much improving I have to do in all aspects of my game and all departments of my game, and if I can have a year like I had in 2010, I can certainly have as good a year again and if not better."

(Editing by Frank Pingue)