The Canadian goes into Round Two at Kiawah Island in South Carolina in the lead.
Canadian Corey Conners leads the US PGA Championship ahead of round two at Kiawah Island.
He shot a 5 under par opening round of 67 in windy conditions.
Padraig Harrington is the best of the Irish trio.
The European Ryder Cup captain made an eagle on the 11th hole en route to a 1 under par round of 71.
Shane Lowry double bogeyed the 17th as he carded a 1 over par round of 73.
Tournament favourite Rory McIlroy has work to do from 3 over par.

Ireland's James Ryan Handed Three-Match Ban Following Red Card
Kildare County Council Honours Kildare Senior Football Team with Certificate of Recognition
Wednesday Morning Sports Update
Kildare’s Best Christmas Ho Ho Home Competition
Ireland's James Ryan Received First Career Red Card In Saturday's Game Against South Africa
RDS To Be Known As 'Laya-Arena' After Major Rebrand
Eadestown Tadgh Beirne Included In World's Rugby Team Of The Year
Tuesday Morning Sports Update