South Korea's Si Woo Kim will try to finish another round atop the leaderboard in the CJ Cup Byron Nelson.
That wasn't easy in the third round and more challenges could await.
Yet Kim recovered from a bad mid-round stretch to shoot 3-under-par 68 on Saturday and maintain the lead through three rounds in McKinney, Texas.
Kim, who opened the day with a five-shot lead, sits at 21-under 192 and carries a two-shot edge over World No 1 Scottie Scheffler and Wyndham Clark going into Sunday's final round at TPC Craig Ranch.
Considering Scheffler won last year's tournament at 31-under, Kim and everyone else in the chase will need to pile up more birdies.
"I think I kind of have to be aggressive, but not too crazy aggressive," Kim said.
After a four-hole stretch when he recorded three bogeys, Kim played the final seven holes in 3 under.
Scheffler, the hometown favourite, and Clark both turned in 65s. Scheffler had only one bogey, but settled for pars on the last five holes.
"He's a great competitor," Scheffler said of Kim. "I'm looking forward to the challenge of going to chase him down tomorrow. He's one of the most talented guys we have out here on Tour."
Scheffler, meanwhile, happens to be the most talented guy on this or any other tour. He proved it yet again in last year's final round at TPC Craig Ranch when he shot a 63 and won by eight strokes.
"I feel like this tournament always has a pretty good energy," Scheffler said. "We get a nice turnout, especially when you get some local guys in the same group. Yeah, I thought it was good energy."
Kim considers Dallas his adopted hometown, so he's normally comfortable in this environment. He's aware that Scheffler has deeper roots.
"He grew up here," Kim said. "It's going to be a lot of fans cheering for him. I know, of course, everyone's cheering for him."
Clark said the final round could become a shootout with scores potentially going low.
"It's also fun to be going out there and who's going to make the most birdies, who's going to hit the best shots and make the most putts," Clark said.
Tom Hoge (66), South Korea's Sungjae Im (67) and Germany's Stephan Jaeger (64) are tied for fourth at 17 under.
Kim reached 20-under with birdies on two of the first six holes before a bogey on the par-4 eighth. Bogeys on Nos. 10 and 11 dropped him into a tie for the lead.
"After that, my caddie told me, you're in the rush," Kim said. "So you've got to calm down and try to think a couple more things."
Clark played the front nine in 5 under, boosted by an eagle on the par-5 fifth hole when he needed a putt of less than 6 feet.
Jaeger enjoyed the day's best round. He opened with birdies on the first three holes and delivered another three-birdie stretch on Nos. 12-14.
Tee times for the third round were delayed and adjusted because of weather-related concerns. Golfers were paired in threesomes starting on Nos. 1 and 10.