England's Justin Rose topped the leaderboard with a one-shot lead after firing a six-under 64 on day two of the Fort Worth Invitational in Texas.
Rose had entered the day tied in eighth but the Englishman hit seven birdies - including three in a row on holes 14 to 16 - with a bogey at the par-three eighth the only blemish of his round as he moved to 10 under par overall.
The 37-year-old, hoping for his second tour win this season, said: "I did a lot of good things today.
"I think the end of my round got a little scrappy, but until the last three holes it was pretty flawless. I think I hit every fairway pretty much and obviously every green to that point.
"Actually, I left a few out there on the greens early but didn't get frustrated. Fooch (Mark Fulcher, Rose's caddie) had a little word with me, just said, 'Hey, mate, just kind of stay patient'.
"That was great advice because I made a little eight, 10-footer which took the lid off the hole, my fifth hole of the day.
"From there got into a nice rhythm, really. The way I played through... I guess through my first 15 holes today was about as good as I've played in a long time," he said, speaking to the PGA Tour website.
Argentine Emiliano Grillo, tied in third after day one, was the new second-place man on nine-under overall, a 33ft birdie on the par-three fourth the highlight of his three-under 67 round.
First round leader Kevin Na dropped to joint sixth after a disappointing round of three-over par, including four bogeys and a double bogey on the par-four 12th.
