Defending champion Graeme McDowell was in upbeat mood after playing his first practice round of the week at US Open venue Congressional.
McDowell played alongside fellow Irishman Shane Lowry and qualifier John Ellis and said he was "buzzing".
"My energy levels are good and I really enjoyed my practice round," said McDowell, who triumphed at Pebble Beach last year.
"The golf course is up to speed and I can see a way around it."
McDowell added that the course was a different proposition to what he had faced during a reconnaissance visit to Maryland a number of weeks ago.
"Then it was cold, it was wet and a difficult test.
"We enjoyed the golf course this morning and I did have a little spring in my step.
"It's very different to be here as the defending champion and very exciting to come to a golf course and I guess know that you have the capability to win it.
"Typically, when you come to a US Open type set-up, you're always in awe of it and of how difficult it is.
"But if you know you can do it, you can win over 72 holes on one of the toughest tests there is, it gives you a lot of confidence."
McDowell acknowledged that the Maryland venue will be a more exacting examination of the long game than was the case 12 months ago at Pebble Breach.
"It's going to test every aspect of the game. You've got to drive it well.
"By modern standards, Pebble Beach is not the longest golf course but this golf course is long.
"You've got to drive it and hit three woods and really position it well off the tee as these greens are really, really difficult.
"(With the approach shots) You have to keep it under the flags. Over the back of these greens is typically dead.
"You are really going to have to play smart going into these greens."
McDowell has confirmed that he will compete in the Dunlop Phoenix event in disaster-ravaged Japan in November.
"Like everyone, I have been truly saddened by the hardship and suffering caused to so many Japanese people," said McDowell.
"I look forward to trying to bring some joy to the people of Japan."
McDowell played in the tournament in 2002 when he finished in a share of 44th place.