Americans Blake Adams, Jason Bohn and Jeff Overton all fired seven-under 63 in the first round of the PGA Colonial on Thursday.
Former champion Phil Mickelson, who needs a win this week to surpass Tiger Woods as the world No. 1, struggled to a one-over 71 and was tied for 89th place.
Mickelson, the 2008 champion, got off to a quick start with birdies on his opening two holes, but couldn’t keep it up.
A Mickelson win would give him his third career Colonial triumph and the top ranking for the first time in his career, but he has a lot of work to do after his disappointing round.
“There’s no excuse. There’s no wind, the golf course is in perfect shape and there were a lot of scores out there,” Mickelson said. “I just wasn’t one of them.”
Mickelson did not play in this event last year because his wife Amy had been diagnosed with breast cancer.
England’s Brian Davis was alone in fourth with a six-under 64, while defending champion Steve Stricker fired a 68.
There was a group of nine players at 65, including Australians Nathan Green and Aron Price. They are one shot better than John Daly, who had his first bogey-free round in two years.
Davis left immediately after his round to get some treatment for an abscess inside his mouth which had left his face swollen.
Mickelson bogeyed two of the last three holes, saving par at 17 despite his approach shot hitting a television tower.
Like Davis, Bohn also had a planned visit to the doctor once his round was complete. Bohn, who won last month in New Orleans, played through the pain of ear trouble to fire a season-best round.
Bohn said he woke up in the middle of the night with sharp pain in his left ear.
Overton, who teed off in the first group of the day, shot a backside six-under 29, which was one stroke off the course record.
He had one 10-hole stretch that featured seven birdies beginning on the eighth hole.
Britain’s Luke Donald gained quick consolation for missing out on Europe’s PGA title last week by firing a seven-under 65 to earn a share of the Madrid Masters first-round lead on Thursday.
Donald hit two spectacular eagles to share top spot late in the day with fellow Britons Rhys Davies and Jamie Donaldson.
“I can’t remember when I last made two eagles in one round,” the delighted world No. 13 told reporters.
A double-bogey on the 71st hole last week at Wentworth scuppered Donald’s chances of glory in the PGA event and relegated him to joint second behind Simon Khan.
This time on the 17th he made one of four birdies to go with his eagles after starting his round with a bogey.
A Ryder Cup place is Donald’s goal and now Irishman Paul McGinley suddenly found it on his radar too after a 66 earned him a share of fourth place with Dutchman Maarten Lafeber.
McGinley, 43, is strongly tipped to be one of Colin Montgomerie’s vice-captains for this October’s Ryder Cup match, but Montgomerie has given McGinley until after The Open in July before he will approach him to act as an assistant in case he plays his way into the team.
McGinley sank the winning putt to earn Europe the 2002 honors against the US and has been on the victorious side in each of his three Ryder Cups.
A spectacular chip-in for an eagle on a flawless card also containing four birdies showed McGinley was on his way back after another knee operation in November last year.