American Jason Kokrak put himself in a great position to win a first PGA Tour title at the AT&T Byron Nelson as Jordan Spieth had a day to forget.
Kokrak fired a stunning 62, just two shots more than the course record, to move five clear in the lead on 12 under at the halfway point at TPC Four Seasons.
The 31-year-old sank eight birdies in his blemish-free round and he will now aim to complete the job over the weekend and get his first taste of success on the tour.
One man who will not be around for the weekend, though, is Spieth after he missed the cut following a bogey-laden 75.
It was on the par-five 16th where the real damage was done as he had to take three tee shots on his way to a nine after sending his first two attempts out of bounds.
Kokrak, who has not finished in the top 10 of an event this year, is being hunted down by Billy Horschel, who is five shots back on seven under.
World number one Dustin Johnson is one of six men on six under after a three-under-par 67 and he will hope to be in contention come Sunday night.
Reigning champion and recent Masters winner Sergio Garcia is 10 shots off the lead after a superb round of 65, recovering from what was a poor first round.
Ireland's Seamus Power carded a second round 69 to leave him two under par overall. Birides on the seventh, 10th and 16th were undone by bogeys on the sixth and 17th. He is in 25th place and comfortably makes another cut on the tour.
