Australia's Marc Leishman holds a one-shot halfway lead at the AT&T Byron Nelson in Texas after following his stunning opening round 61 with five-under-par 66.
The 34-year-old was unable to reach the exhilarating heights of his opening round, but still produced six birdies against a single bogey at Trinity Forest Golf Club in Dallas.
At 15 under par Leishman leads by one from American Aaron Wise - the 21-year-old who finished second on his last appearance at the Wells Fargo Championship.
Seamus Power, who was best of the Irish after round one, had a day to forget.
The Waterford man missed the cut after a 74, while Padraig Harrington's round of 70 also means that there is no weekend action.
He finished on three under, as did Grame McDowell, and both missed the cut by one shot.
Leishman, who won twice on the PGA Tour last season, started on the back nine and holed a 55-foot birdie putt at the 12th before picking up another shot on the 14th.
Finding two bunkers cost him a dropped shot at the 15th, but four birdies in five holes from the first kept him ahead of the chasing pack.
"I'll certainly take that - when you shoot a really low one like I did yesterday then it's hard to back it up," Leishman told the PGA Tour website.
"There probably was a few more out there but I holed a couple of good putts."
Wise fired six birdies and an eagle in his round of 63, with compatriot Brian Gay a shot further back on 13 under after a round of 62.
