Matt Kuchar fired a seven-under-par 64 to move within two strokes of defending champion Justin Leonard after three rounds of the Texas Open at the LaCantera Golf Course in San Antonio.
Kuchar, the 1997 US Amateur champion, had seven birdies in a bogey-free round as he seeks his first PGA Tour victory.
He will be paired in the final round with Leonard, who won the Amateur title in 1992.
"I have not been in contention before. I'm excited about it," Kuchar said. "It takes a lot of work to play out here."
Leonard carded a 68 for a 54-hole total of 16 under par on 197 as he tries to become the first Texas Open repeat winner since Arnold Palmer in 1961-62.
"I did not play as well," said Leonard - who began the day with a three-shot lead. "I missed a couple of tee shots. I did not give myself a chance the last four holes. I did not keep pace with Thursday and Friday."
Carl Paulson shot a three-under 68 and finished the day where he started it - three shots behind Leonard.
First-round leader Marco Dawson, Tom Scherrer and J.J. Henry are five strokes off the pace on 202.
Dawson needs a top-three finish to retain his PGA Tour card.