Shane Lowry is three shots off the lead at the Memorial Tournament after carding an opening round of 69 in Ohio.
The Offaly man is tied for seventh on three under after hitting four birdies during his round before a bogey on 17.
PGA Championship winner Collin Morikawa is on top of the leaderboard by one shot after a weather-affected first round.
The American started his round on the back nine with three birdies in his opening nine holes and a bogey on the par-four 18th.
But he recovered with three consecutive birdies and added a seventh to sign for a 66.
Adam Long finished on a five-under 67 while four others are a shot further back, including world number five Xander Schauffele, while Matt Wallace is the highest placed Briton on one under.
Rory McIlroy, Louis Oosthuizen, Jordan Spieth and Bryson DeChambeau will resume their first rounds on Friday morning after play was called off on Thursday evening due to inclement weather.
