Russell Knox holds a one-shot lead after the opening round of the Valero Texas Open, while Rory McIlroy experienced an eventful start at TPC San Antonio.
The world No 169 made four consecutive birdies on the back nine to post a bogey-free 65, giving the Scot a narrow advantage over Denmark's Rasmus Hojgaard, with England's Aaron Rai among the group two off the pace.
Knox followed an opening-hole birdie by picking up a shot at the fifth and holing from off the green at the par-four seventh, with his run of birdies from the 12th taking him to seven under.
The winner of this week's event will secure a last-minute invite to The Masters, with Knox among the players needing the victory to qualify for the opening men's major of the season.
"I would love to win and get to play next week," Knox said. "That's obviously why I'm here and everyone should be playing. I know my game is good, so I've got to keep playing and see if I can have a great finish."
Hojgaard rolled in a 40-foot eagle at the 18th to reach the turn in 30 - having started on the back nine - and topped the leaderboard when he added birdies at the first and sixth, only to slip back after double-bogeying his final hole.
Matt Kuchar made four birdies in a five-hole stretch on his way to an opening-round 67, with JJ Spaun holing out from 87 yards for eagle at the par-five eighth and Denny McCarthy carding an eagle at the par-five 14th to both also get to five under alongside Rai.
England's David Skinns is in the group three off the pace and Scotland's Robert MacIntyre opened with a three-under 69, while Richard Bland sits in a share of 30th after a two-under 70.
McIlroy mixed six birdies with as many bogeys on his way to a level-par 72, with the Northern Irishman almost holing out at the 17th after seeing his tee shot roll underneath a parked car.
Defending champion Jordan Spieth is also seven back alongside Rickie Fowler, while Bryson DeChambeau and Lee Westwood both started with a one-over 73.
Hideki Matsuyama, who will defend his title at The Masters next week, struggled to a two-over 74 despite finding five birdies during the opening day.
Watch the Valero Texas Open throughout the week live on Sky Sports. Live coverage continues Friday with Featured Groups from 1.30pm on Sky Sports Golf.