Golf: Camilo Villegas and Zach Johnson share lead at the US PGA Tour event in Illinois

Colombia's Camilo Villegas deployed a "chill" attitude and a hot putter to seize a share of the first-round lead alongside defending champion Zach Johnson at the US PGA Tour event in Silvis, Illinois.

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.

His 7-under-par 64 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."

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

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

Matt Jones is the best-placed Australian in a seven-way share of sixth position on 5-under following an opening round of 66.