Dustin Johnson and Luke List carded six-under-par 66s to take a one-shot lead at the RBC Canadian Open on Thursday.
Johnson and List are closely followed by Chesson Hadley, Kelly Kraft, Jared du Toit and Jon Rahm, who all fired five-under-par 67s.
Meanwhile, world number one and defending champion Jason Day is three strokes adrift of the lead in a tie for 11th.
Johnson, who triumphed at the WGC-Bridgestone Invitational earlier this month, began his round with a hat-trick of birdies from the third to fifth before faltering with a bogey at the ninth. The reigning U.S. Open champion atoned for his mistake by making three birdies on his first four holes on the back nine before recording a double bogey at the par-four 14th, where his approach shot fell into the water.
Despite the setback, Johnson made a birdie at the 16th and found himself in a share of the lead after making a 10-foot eagle putt at the par-five 18th.
List kicked off his round with a 13-foot birdie putt at the 10th and went on to make four more birdies on his front nine, which included an incredible 54-foot putt at the 15th. The American had a much quieter back nine as he only made a lone birdie at the second, but it was still enough to put him in a share of the lead.
Hadley enjoyed a highly successful round as it consisted of six birdies and a bogey, while Kraft made four birdies, a bogey and a 17-foot eagle putt at the 18th. Du Toit recorded five birdies, a double bogey at the par-three seventh and an eagle at the par-four 17th, where he sunk his approach shot from 155 yards, during his round. Rahm, meanwhile, made seven birdies, which included a 27-foot putt at the 12th, and two bogeys.
Meanwhile, Day began his round of 69 with two birdies on his first four holes before he made consecutive bogeys at the 14th and 15th. He recovered by registering a birdie at the 16th before going on to make a chip-in eagle from the right rough at the par-five second. A 13-foot birdies followed at the fourth before the Australian finished his round with a bogey at the seventh.
Bryson DeChambeau hopes his victory at the Rocket Mortgage Classic on Sunday has answered his critics.
Overnight leader Matthew Wolff was not able to recover from a poor start.
Americans Ryan Armour and Bryson DeChambeau sit in second place.
The Englishman carded a 66 to put behind him the disappointment of playing alone and missing the cut last week.
Webb Simpson isn’t bothered by the number of the positive tests on the PGA Tour.
The 26-year-old California native revealed he has stuck to a 3,500 calorie a day diet.
The American was forced to pull out of the Rocket Mortgage Classic.
The world number one has become frustrated by errors that have kept him out of contention.
Brendon Todd led the way after the third round of the Travelers Championship.