Padraig Harrington insists his desire to win the US Open is stronger than ever now he has tasted major championship glory.

The Irishman won the Open Championship last summer after beating Sergio Garcia in a play-off at Carnoustie.

And ahead of Thursday's start, Harrington says he is feeling the added pressure at Torrey Pines.

"The US Open obviously brings a certain element of expectation and puts a bit more stress in a week like this," Harrington said.

"Having won a major as a player, you want to go on and win two."

Last year's Carnoustie win not only led to higher expectations, but also to a more hectic schedule.

"Last year for the six months up to Christmas, it was incredibly busy," he said.

"A lot of things to be done, a lot of extra pressures and stresses outside the game.

"I think on the golf course, it brings a certain level of expectation and there's no question you probably try a little bit harder when you're on the course."

Harrington tied for fifth at the Masters and is coming off a tie for fourth at the St Jude Championship last week.

He has been able to get his game back in order as the excitement around his major victory has died down with the start of a new season.

"It's easier to focus on going forward when you are in a new year," Harrington said.

"You put it to the back of your mind.

"I played the last two weeks, and I've been getting into my focus. My concentration is getting better, my thinking on the golf course, my sharpness, all those things have been improving.

"I'm happy with the last two weeks and I feel ready to go play this week. That's all I can do."