Ryder Cup team-mates Padraig Harrington and Lee Westwood led the European bid to succeed Paul Casey on the Shell Houston Open victory podium after the defending champion withdrew due to injury.
Ireland’s Harrington and Englishman Westwood each shot a three-under-par 69 at Redstone Golf Club in Humble, Texas, to lie two shots behind first round co-leaders Kevin Stadler of the United States and Australian Cameron Percy.
England’s Casey, who landed his first US PGA Tour victory in the event 12 months ago, had earlier suffered a blow to his Masters build-up when he was unable to defend his title.
The world number six, who was due to partner Phil Mickelson in the opening two rounds, tweaked a muscle in his back near his left shoulder and withdrew just before his 8am tee-off time.
Casey said it was not related at all to the torn chest muscle which kept him out of action late last season and hoped it was a just a “sleeping wrong” problem which would quickly respond to treatment.
In his absence, Ireland’s Harrington was the pick of the early European starters, the three-time major winner continuing his good recent form with a five-birdie, two-bogey opening round.
He was joined on three under by Westwood, who shot a bogey-free 69 and like all the afternoon starters had to deal with far more windy conditions than the earlier wave.
Americans Anthony Kim, Vaughn Taylor, Kevin Sutherland and James Driscoll were in a tie for second on four under with Harrington, Laird and Westwood in an eight-man group that also included Mickelson and Australia’s Adam Scott.
Scotland’s Martin Laird was a further shot behind on two under having finished bogey, birdie, bogey playing the front nine last and also shooting a 70 were England’s Justin Rose and South African Ernie Els, who is bidding for a third straight win following successes at the CA Championship and Bay Hill Invitational.
Dubliner Harrington had gone on a run of birdies at the 14th, 15th and 16th but then his second bogey of the round came at Redstone’s tricky 488-yard, par-four 18th.
“The round was really going nowhere until I hit 14,” Harrington said. “I had some chances early on and 10, 12 and 13, I actually played them one-over par.
“I’m not feeling too good about the game. I hit the flag on 15 with my pitch and made birdie there, and then I hit it close on 16.
“I really went from nowhere to a good round, and obviously 17, 18, especially 18 is a hard hole. I wasn’t feeling on top of my game today. It was kind of hard there.”
Of his experience at the 18th, where Harrington over-compensated for the lake down the left of the fairway by finding a right-sided bunker, he said: “I wasn’t very confident in myself. Tough tee shot when you’re not feeling too good.
“I did well with the bunker shot, 25 yards into the wind with the water behind it. I thought the difficulty was getting it to the hole, to run it out, 10 feet past. Hopefully, a lot more golf to be played.”
Harrington, though, claimed he was content to take a 69 from his opening round.
“I’m pleased enough with the score,” he added. “I didn’t hit it very well on the range before I went out and a little bit conservative all the way around. I was never quite sure of myself. I was happy to play the golf I played.
“I made the most of my opportunities when they came around. I got a nice birdie run on the back nine, three in a row got me into the tournament.
“I was not quite confident enough how I was hitting to it play the tough hole like the last. I managed to drop a shot by being very conservative off the tee.”
Masters champion Angel Cabrera, Germany’s Martin Kaymer, Sweden’s Carl Petterson and Denmark’s Soren Kjeldsen all carded 71s and Englishman Chris Wood shot a 72.
England’s Luke Donald and Simon Dyson, and Sweden’s Fredrik Jacobson finished the day with 73s, one over par.
Northern Ireland’s Rory McIlory had a card showing three birdies, three bogeys and double bogey as he posted a two-over 74 alongside Norway’s Henrik Bjornstad, while Sweden’s Daniel Chopra hit a 75 and England’s Brian Davis signed for a 76.
Greg Owen’s round began brightly with birdies at two of his first three holes but it was all downhill from there.
The Englishman hit seven bogeys and one double bogey in his remaining 15 holes to close with a 79, seven over par before withdrawing due to illness.
Vijay Singh had been seven over after nine holes when the Fijian withdrew from the tournament citing a bad back.