China's Dou shares Byron Nelson lead with Palmer and Eckroat
Dou looked right at home on the par-71 TPC Craig Ranch course just minutes away from where he makes his US home in suburban Dallas.
He and Eckroat top the leaderboard after 54 holes for the first time in their PGA Tour careers as they chase a first title, while Palmer claimed the most recent of his four wins in 2019.
"I do feel some nerves already," Dou admitted not long after he capped his 64 with a two-putt birdie at the par-five 18th.
Eckroat had 10 birdies to overcome a double-bogey in his eight-under 63 while Palmer joined the group on 16-under 199 with his sixth birdie of the day at the par-five 18th
Palmer's 35-foot eagle putt was headed for the heart of the cup but stopped on the lip, giving him a three-under par 68.
The leading trio were two strokes in front of a quartet headlined by world number two Scottie Scheffler, who was joined by Australian Jason Day, Sweden's Vincent Norrman and South Korean Kim Si-woo.
On a windy afternoon in north Texas, Dou got things going with a 19-foot birdie at the second and added a 15-footer at the fifth, then blasted out of a bunker to three feet for birdie at the sixth.
He drained a 20-foot birdie at the 13th, and got up and down for birdie at 14 and again at 16 -- where he was in a cart path off the tee but gave himself a 28-foot birdie chance and made it.
Dou kept things going with a chip to one foot to save par at the par-three 17th.
Along the way, he said, he tried not to pay too much attention to the leaderboard.
"I know I'm playing pretty good. I don't want to have to know who's in the lead, how much back I am to get in my head, and mess up shots," said Dou, who missed eight cuts in 17 prior starts this season.
Scheffler stumbles
Eckroat, who is from Oklahoma, also expected to be feeling some nerves on Sunday.
"You put yourself in this position and you kind of feel like a win is the only way that it's a successful week," he said. "But (I'll) just go out tomorrow and try to play the best I can and see what happens."
When he walked off the 18th green, Eckroat had high expectations of playing in the final group on Sunday alongside Scheffler.
But former Masters champion Scheffler, who held the overnight lead, struggled on the greens and after two bogeys and three birdies was one off the lead through 17 holes.
At 18, he was in a fairway bunker off the tee and failed to get the ball out with his second shot on the way to a bogey for an even par 71.
Norrman carded a 65, Day shot 66 and Kim signed for a 68.