A round of 61 has seen Charley Hoffman surge to the top of the leaderboard at the Travelers Championship in Connecticut.
The American shot five birdies and two eagles on his first trip around River Highlands - one better than Hunter Mahan, who challenged at last week's US Open.
Mahan reached the turn in five-under-par and was on for a 59 round as he approached the final three holes, but he could not find the extra shot needed to break 60.
Bubba Watson is third on seven-under, two strokes ahead of John Merrick, Webb Simpson, Rod Pampling, Camilo Villegas and Graham DeLaet.
US Open winner Justin Rose was one-over-par through 11 holes but a bogey-free back nine with birdies at 12, 13, 15 and 16 seeing him finish one three-under-par, the same score as Lee Westwood.
Meanwhile, a nine at the par-four 17th hole contributed to a three-over round of 73 for Ian Poulter, despite his improved showing at Merion.
