World number one Dustin Johnson sits three shots off the lead following the opening round of the AT&T Byron Nelson in Texas.
The American, who is stepping up his recovery from the back problem which ruled him out of last month's Masters, carded 67 at the Four Seasons Resort and Club in Dallas to finish the day three under par.
Seamus Power finished on one under, five off the lead and in a share of tied 26th in a crowded leaderboard and the Waterford golfer will be hoping for another strong showing on Friday to at least ensure he stays around for the weekend.
The competition is Johnson's third since the injury after he finished tied for second at the Wells Fargo Championship and was joint-12th in last week's Players Championship.
Johnson's compatriots James Hahn and Ricky Barnes hold the joint overnight lead on six under, while Matt Kuchar, Jason Kokrak, Cameron Tringale and Venezuelan Jhonattan Vegas are all two strokes off the pace. Jordan Speith is a shot behind Johnson on two under.
Defending champion Sergio Garcia, who also won the tournament in 2004, has plenty of work to do after he hit three bogeys during a first-round 73 which leaves him three over, though Ian Poulter is on even par.
"It was really difficult today, the way it was blowing hard and it was gusty," Johnson said.
"It was very difficult to judge the wind. My short game was pretty good today. I made some nice saves to keep the round going," added long-hitting Johnson, who needed just 24 putts.