IRVING (Texas) (REUTERS) - American Brooks Koepka made three birdies on the back nine to charge past hometown favourite Jordan Spieth and into a two-shot lead after the AT&T Byron Nelson third round in Texas on Saturday.

Koepka posted a five-under for a 16-under total at the TPC Four Seasons Resort in Irving, while Spieth closed with bogeys at the 14th and 18th for a 67 to drop back into second place.

US Open champion Spieth held the outright lead but an errant tee shot at the par-four 14th found water, resulting in his first bogey of the day and a two-shot swing there as Koepka drained a 20-foot birdie putt.

Americans Matt Kuchar (65) and Bud Cauley (68), and Spaniard Sergo Garcia (68), were tied for third at 13 under while overnight leader Ben Crane struggled to a 72 to fall six strokes off the pace.