Paul Casey is the clubhouse leader at the Masters after shooting a 7-under 65 in the opening round in Agusta, Georgia.
Casey got on a roll Thursday with an eagle at the par-5 second hole.
He added on five more birdies to match his lowest score ever at The Masters, grabbing a two-shot lead over Webb Simpson and Xander Schauffele.
Almost half the field unable to complete the first round because of a three-hour weather delay in the morning.
Tiger Woods is at minus-4 as he seeks a record-tying sixth Masters title.
It matched his lowest start ever at the Masters, and it was his first bogey-free round in a major since the opening round of the 2009 PGA Championship at Hazeltine.
Mike Weir had a solid day as the 2003 Masters champion from Brights Grove, Ontario fired a 1-under 71.
Nick Taylor of Abbotsford, B-C was 1 under through 12 holes when play was halted. Abbotsford's Adam Hadwin and Corey Conners of Listowel, Ontario opened with 2-over 74s.
With files from the Canadian Press and the Associated Press