A third round 63 catapulted rookie Austin Eckroat into a share of the lead heading into the final round of the AT&T Byron Nelson near Dallas as home favourite Scottie Scheffler slipped back.

Eckroat, chasing his first PGA Tour win and a place in the USPGA Championship which begins at Oak Hill on Thursday, heads into the closing round tied with China’s Zecheng Dou and fellow American Ryan Palmer.

They hold a two-stroke cushion over Scheffler, former USPGA champion Jason Day, Si Woo Kim and Sweden’s Vincent Norrman with England’s Tyrrell Hatton among those a shot further back.

Eckroat mixed seven birdies and a double bogey in his front nine and had no doubts about what winning would mean.

“A lot of job security,” he said. “A lot of things come with winning a PGA Tour event and just hoping to get that done.”

Palmer missed an eagle putt on the last to take an outright lead while Dou, playing on his home course TPC Craig Ranch after settling in Dallas, fired a 64 after contrasting opening rounds of 63 and 70.

“There is a whole lot more golf to play, so I’m good in the position like this, creating more chances. That’s all I’m thinking,” he said.

World number two Scheffler had opened with a pair of 64s and missed a short birdie putt to take a two-shot lead on the 12th but squandered chances coming home before needing two goes to get out of a fairway bunker on the 18th.

Hatton, the second-highest ranked player behind Scheffler at 17, moved into contention with three closing birdies to round off a bogey-free 65 that leaves him alongside South Korean Sung Yang and Americans Richy Werenski and Patton Kizzire.