Padraig Harrington is just two shots off joint-leaders Louis Oosthuizen and Brendon Todd after round three of the Byron Nelson Championship after a third-round 66.
The Dubliner is eight under par heading into the final round in Texas.
Oosthuizen fired a round of 64 to hold a share of the lead going into the final day.
The South African had a run of consecutive birdies on the 14th, 15th, and 16th to cap a superb round which moved him up 14 places on the leaderboard.
Overnight leader Todd did enough to retain a share of top spot, but needed a birdie on the 18th to do so after a bogey on the fourth saw him fall behind. He signed for a two-under 68.
Oosthuizen claimed the best round of the day but James Hahn was one bogey on the 11th away from matching it, with a stunning run of birdies between the 12th and 16th catapulting him up to a share of third place alongside Gary Woodland and Mike Weir.
Woodland was in there despite a horror show on the par-five fifth, where he got stuck in the sand and wound up with a double bogey.
Weir had an up-and-down round himself, with six birdies and two bogeys.
Another man left kicking himself at the end of play was Morgan Hoffman, who had looked good to hold a share of the lead before finding a bunker on the 18th and dropping two shots there to slip back into a tie for sixth.
It was his second double bogey of the round after woes on the 11th, and combined with a bogey on the eighth it served to wipe out most of the shots picked up from seven birdies.