Padraig Harrington will begin his US Masters challenge in the company of Canada's Mike Weir and Jeev Milkha Singh of India on Thursday.

The 2007 Open champion will tee off at Augusta National at 3.34pm (Irish time), playing his opening two rounds with Weir and Singh.

Harrington admits to being "a little more relaxed this year" but knows that the course demands respect and top form in every facet of the game.

"I always say when you come here, the test is right there," the Dubliner said today. "It's not good enough to hit your iron shots straight into the greens. They have got to be struck right so that they land in the right sections and also stop in the right section.

"I think of all of the courses you've got to be 100 per cent here. Coming down the stretch, hitting into all the greens through the back nine, there's an awful lot of intimidation factor on those holes, and you've got to be spot-on."

World number one Tiger Woods will tee off with US Open champion Angel Cabrera and Australian Stuart Appleby.

Woods begins his quest for a fifth green jacket at 3.45pm alongside Argentinian Cabrera, who held him off to win the US Open at Oakmont last year.

Appleby had the lead in Augusta after three rounds last year and played with Woods in the final group on Sunday.

England's Luke Donald faces defending champion Zach Johnson and Australia's Geoff Ogilvy at 3.23pm.

Phil Mickelson goes in search of his third green jacket at 6.41pm and will be accompanied by Andres Romero of Argentina and KJ Choi of South Korea.

Arnold Palmer will start the event with a ceremonial first tee shot at 12.50pm.