Rookie Jake Knapp grabs one-shot lead over Matt Wallace at CJ Cup Byron Nelson

Overnight leader Matt Wallace fell back to equal-second on the leaderboard after following up a first round 63 with a round two score of five-under 66, splitting an eagle and four birdies with a bogey on the first hole.

"Really stuck in there well," he said. "Hitting the ball great off the tee. My long iron play can improve a little bit, but I still hit some really nice shots."

Wallace sits on 13 under par alongside American Troy Merritt, who rocketed up the leaderboard on Friday with a stellar round of 62, which included an eagle on the final hole.

Merritt's compatriot Knapp poked his nose in front with a second straight round of 64 to head into the weekend on 14 under.

"For the most part hitting it pretty solid and keeping in the right areas," Knapp said. "Made it relatively easy on myself. Never really felt like I had to scramble or anything like that."

Knapp won his first PGA title at February's Mexico Open and is getting used to being in contention.

"I feel comfortable. I've been there before," he said. "Courses like this where scores are going to be low you don't worry too much about what other guys are doing. You try to make a bunch of birdies. If I just keep doing the things I'm doing I'll be in a good spot."

World number 20 Jordan Spieth – the highest ranked player in the field – missed the cut by two strokes as he finished on four under par.

Meanwhile, 16-year-old English amateur Kris Kim became the youngest player to make the cut on the PGA Tour since 2015, clearing the bar with a four under 67 on Friday to head into the weekend on seven under par.