By Andrew Both
AUGUSTA, Georgia (Reuters) - The past 12 champions at the U.S. Masters have all shot 71 or better in the first round, which is good news for Rory McIlroy and Phil Mickelson, not so much for some of the other favorites.
Tiger Woods with a 74 in 2005 was the last man to don a Green Jacket after starting poorly.
McIlroy (69) and Mickelson (70) were well pleased with their starts on Thursday, a day when Jordan Spieth took advantage of benign afternoon conditions to set a cracking pace at six-under 66 at Augusta National.
Northern Irishman McIlroy, going for the final leg of the career grand slam, said his first round score would allow him to be a bit more patient.
"It's such a hard course to play catch up on," McIlroy said after breaking 70 in the first round for only the second time in 10 starts at Augusta.
"If you start to chase it around here, that's when you start to make mistakes. But to be right up there and have the ability to stay patient, because of the position I'm in, that's a nice luxury I have over the next few days."
Mickelson recovered from a slow start to keep alive his hopes of a fourth Green Jacket.
"I just wasn't quite sharp," said the 47-year-old Californian.
"I didn't strike it the way I wanted to. My short game wasn't quite as sharp as I wanted. And I didn't capitalize on some putts that I've usually been making.
"But what I did do well is plot my way around the golf course. I got in a reasonable score."
World number one Johnson was three-over after 10 holes, and in the end was not too fazed by his ordinary score.
"I feel like the game's in good form. I just need to roll in some putts tomorrow, that's all," he said.
World number two Thomas double-bogeyed the par-three 16th and said his round had been ruined by four holes.
"Four holes killed me today, which is a bummer," said Thomas.
Day made an awful start, four-over after seven.
"I just got to keep pushing, just try and claw myself back into the tournament," lamented the Australian.
(Editing by Peter Rutherford)