Johnson shares PGA lead

Villegas, who claimed the last of his three US PGA Tour titles in 2010, has struggled through an indifferent 2013, with just two top-10 finishes in 16 starts.

But he looked every inch a contender on Thursday, however, especially on the TPC Deere Run greens.

His round included a stretch of five consecutive one-putts, and he opened the back nine with four birdies in five holes, nabbing the last of eight birdies at the par-five 17th.

"Made some great putts and just kept out of trouble," Villegas said. "I was very pleased with the way I handled myself out there. It was a nice, relaxed, chill attitude, and I enjoyed every single bit of the round."

Villegas said he's made a concerted effort to find that enjoyment, even as his victory drought continues.

"This job is great when you're playing good," he said. "It kicks your butt when you're not performing. But you can kick your butt even harder when things are not going good. So I'm trying not to be that guy that kicks his butt a little bit harder, just enjoy every second of it."

Johnson had seven birdies with no bogeys to find himself back atop the John Deere leaderboard.

Johnson, of nearby Cedar Rapids, Iowa, notched his 17th straight round in the 60s on the par-71 Deere Run layout.

"I have always felt comfortable here," Johnson said.

He and Villegas were one stroke in front of Matt Bettencourt, Daniel Summerhays and Zimbabwe's Brendon de Jonge, who all carded 65s.

Colonial winner Boo Weekley led a group of seven players on five-under that also included Australian Matt Jones, Canadian David Hearn, Jim Herman, Vaughn Taylor, Kevin Streelman and Robert Streb.

Steve Stricker, who had his three-year winning streak in the tournament snapped by Johnson last year, was in a group of 13 players on 67 which also included South Korean K.J. Choi and US veteran Davis Love.

Leading first-round scores on Thursday in the $4.6 million US PGA John Deere Classic (USA unless noted, a-denotes amateur, par-71):

64 - Zach Johnson, Camilo Villegas (COL)

65 - Brendon de Jonge (ZIM), Matt Bettencourt, Daniel Summerhays

66 - Vaughn Taylor, Robert Streb, Jim Herman, Kevin Streelman, Boo Weekley, Matt Jones (AUS), David Hearn (CAN)

67 - Martin Flores, Ryan Moore, K.J. Choi (KOR), Steve Stricker, Davis Love, Lee Williams, Steve LeBrun, a-Patrick Rodgers, Patrick Reed, Tom Gillis, Chris Kirk, Nick Watney, Donald Constable