Tony Finau is one of four players with a share of the lead after finishing Thursday's opening round of the Houston Open with a five-under 65.
Finau is joined by fellow Americans Aaron Wise and Tyson Alexander, as well as Sweden's Alex Noren, although Alexander still has one hole to play as the late-starters had their rounds cut short when darkness halted the action.
Ranked 15th in the world, Finau caught fire on his second nine, posting five birdies from his final eight holes to fly up the leaderboard.
Canadian duo Taylor Pendrith and Mackenzie Hughes headline the logjam tied for fifth at four under, with England's Justin Rose part of the 10-player group one further back at three under.
It was a rough day out for the big names in the field, with world number two Scottie Scheffler and former Masters champion Hideki Matsuyama shooting even-par 70s to finish the round tied for 53rd.
That pairing at least remain in the hunt, which is more than can be said for last week's winner of the World Wide Technology Championship at Mayakoba, with Russell Henley struggling on his way to two over.
Another former Masters champion had a tough time, with Danny Willett unlikely to make the cut after his five-over 75, while world number 12 and recent Presidents Cup debutant Sam Burns had a day to forget, shooting seven over.