Tim Petrovic finished a stellar round with three consecutive birdies to earn a two-shot lead after one round of the Shaw Charity Classic in Calgary, Alberta.

Petrovic turned in an 8-under-par 62, with Harrison Frazar in second place at 6-under 64.

Billy Mayfair shot a bogey-free, 5-under 65 for sole possession of third at Canyon Meadows Golf & Country Club.

Petrovic, 57, has never won on the PGA Tour Champions.

"Expectations were not (high) – but you know what, I've been having some good practice sessions and I think it was just a matter of me, you know, just kind of putting it all together on the golf course," Petrovic said.

Despite playing through tennis elbow and hitting only three of 13 fairways in regulation, Petrovic came one stroke shy of matching his career-low round on the 50-and-older circuit.

He started on the back nine and had one birdie and one bogey through seven holes, but a birdie at the par-4 17th hole and an eagle at the par-5 18th kicked his round into gear.

Petrovic then rolled in five birdies on his second nine, including at Nos. 7, 8 and 9.

"No 7's probably one of the hardest driving holes out here, probably my best drive all day with a 3-wood and my best iron. Hit it about 4, 5 feet," Petrovic said. "On 9, we were just trying to hang onto the club and get it anywhere in front of the green, and I managed to skip it up there and just made a 20-footer."

Both Petrovic and Frazar played early enough to avoid rain and winds that arrived in the Calgary area in the afternoon.

Frazar birdied Nos 1, 2, 4 and 5 for a hot start. After his only bogey of the round on No 7, he added three birdies on the back nine. Like Petrovic, the 52-year-old has also never picked up a PGA Tour Champions victory.

"I feel good about my game right now," Frazar said, "so as long as I don't get too far ahead of myself and start thinking about it too much, yeah, I should be OK."