Updated

Calgary, AB (SportsNetwork.com) - Brock Mackenzie shot a third-round, 5-under 67 on Saturday and he holds a 2-shot lead through 54 holes at the ATB Financial Classic.

At 21-under-par 195 through three rounds, Mackenzie set a record for the lowest 54-hole score since the PGA Tour Canada started. Mackenzie is seeking his second win on tour, with his first one coming at the Times Colonist Open in 2010.

Brady Schnell, who became the first professional golfer to shoot a 59 this season on Friday, is in second place with a 67 on Saturday. Joining Schnell at 19-under is Stephen Carney after his 68 at Sirocco Golf Club.

Cory Renfrew is alone in fourth place at 17-under 199 following a 7-under 65. Sam Ryder (69) is right behind him at 16-under, while Joel Dahmen and Ted Brown are both tied for sixth after a pair of 68s.

Mackenzie, who entered the day with a 1-stroke lead over Carney, made two birdies on the front nine at two and eight, and he made the turn at 2-under for the day.

Back-to-back birdies at 10 and 11 got Mackenzie rolling, but he gave one of those shots back with a bogey at the par-5 13th. He responded quickly, however, with a birdie at the par-3 14th to get back to 4-under.

A final birdie on No. 17 put Mackenzie at 5-under. He made par at the last two end there.

Schnell picked up right where he left off as he tried to follow up on his 59 on Friday. A birdie at No. 2 got him in red numbers early, and four straight birdies from No. 5 vaulted Schnell to 5-under for the day.

A bogey at No. 10 was Schnell's first blemish of the day. He rattled off six straight pars before making another birdie at No. 17. Schnell also parred the last to end there.

Carney had a birdie at the first, but gave the shot back with a bogey at No. 6. Three straight birdies from No. 8 had him rolling, and he added one more gain at No. 13 to move to 4-under. He finished his round with five straight pars.

NOTES: Mackenzie's best finish of the season came at the Bayview Place Island Savings Open, where he tied for second at 11-under ... Schnell has never won on the PGA Tour Canada, and his best finish this year was at the SIGA Dakota Dunes Open, where he finished in sixth ... Carney has missed the cut in four of seven events this year, and his best finish was a tie for 50th at the SIGA Dakota Dunes Open.