Brooks Koepka will take a two-shot lead over Jordan Spieth into the final round of the AT&T Byron Nelson tournament.
The 26-year-old American recovered from two bogeys in the first six holes to sign for a five-under 65 which left him clear at the top of the leaderboard.
Compatriot Spieth, meanwhile, bogeyed the last to drop to 14-under, his round of 67 leaving him one shot clear of Matt Kuchar, Bud Cauley and Sergio Garcia.
Ben Crane, who had been top on Friday night after a round of 63, had three bogeys on his way to a disappointing 72, which sent him down into a share of 11th.
