Thomas Pieters will take a one-shot lead into day two of the WGC-Bridgestone Invitational after a closing birdie sealed a bogey-free 65 at Firestone Country Club.
The big-hitting Belgian has saved his best for the big events all season, with his two top fives thus far coming at the WGC-Mexico Championship and Masters Tournament, and he was at it again in Akron.
He made five birdies to get to five under and lead the way from Scotland's Russell Knox, who is looking for a second World Golf Championships title this week.
World Number Four Rory McIlroy, England's Ross Fisher, Spaniard Jon Rahm, Open Champion Jordan Spieth and fellow Americans Kevin Kisner and Bubba Watson were then at three under.
Pieters started with four pars but a stunning approach to two feet on the 14th got him into red figures before he put his third into the 16th to tap-in range. A putt from the fringe on the first brought another birdie and he made it back-to-back gains despite finding sand with his second shot on the next.
He followed that with six pars but when he rolled in a 31-footer on the ninth, the man who won four points on his Ryder Cup debut at Hazeltine National was in the driving seat.
"I only had two putts from above the hole," he said. "The rest of them were just pretty straightforward putts. I think that was the key.
"I was pretty terrible from the tee but managed to find a lot of greens today. It was kind of a stress-free round. On my back nine, I missed a couple of greens but got up and down a couple of times so pretty happy.
"I've had good results this year, I've been in contention, that's all I want to do. I just haven't had that win. I feel like if I had a win already this year my year would have been good but I just haven't finished it off."
Knox became the first Scotsman to win a World Golf Championships event at the 2015 WGC-HSBC Champions and made an excellent start in his bid to add another as he got to four under.
The 32 year old put his approach into his opening hole to ten feet and then holed a 19-footer to take advantage of the par five 16th. Grazed tree branches led to a bogey on the 18th but he birdied the first and then holed out from 75 yards on the par five next to jump to four under.
He made a smart up-and-down on the fourth, lipped out for birdie on the sixth and made a good save from the sand on the seventh to keep himself in that leading group. An excellent 27-foot putt on the eighth then moved him out in front on his own but he bogeyed the ninth.
McIlroy holed from 25 feet on the 11th but gave the shot back on the 13th before a beautiful approach brought a birdie on the 18th. Back-to-back birdies on the second and third after more excellent approach play moved him further up the leaderboard before he needed a smart par save after a poor second on the fourth.
The 28 year old - who has best friend Harry Diamond on the bag after parting company with JP Fitzgerald - then rolled a 13-footer up the hill on the sixth to sit just one off the lead before bogeying the last.
Fisher bogeyed the 14th to turn in 36 but came alive on the front nine, holing a 25-footer for eagle on the second, putting his tee-shot to three feet on the fifth and then birdieing the ninth after a fine approach.
Rahm had four birdies and three bogeys in a ragged first 14 holes but made an incredible 55-footer from the fringe on the 16th for an eagle that catapulted him up the leaderboard.
Newly crowned Champion Golfer of the Year Spieth had five birdies in his round, one less than Kisner and one more than Watson.
BMW International Open winner Andres Romero, Australian Adam Scott, Canadian Adam Hadwin, World Number One Dustin Johnson and fellow Americans Charley Hoffman and Jimmy Walker were then at two under.
