After the first round of the 3M Open played at TPC Twin Cities, the two leaders – Im Sung-jae and Scott Piercy – sit two strokes clear of the chasing pack at six under.

There was no secret to the pair's success, as both were outlier performers with the putter, topping the day's rankings for strokes gained on the greens. Im was the best at 4.57 strokes gained, with Piercy in second (4.33) – nobody else finished better than Brice Garnett's 3.69.

The success for Piercy came after a week of sweeping changes to his game, entering the tournament with a new coach, new swing, new caddie, new driver and a new putter, saying afterwards that it was nice to be rewarded for his constant quest for improvement.

"I put in the work to make sure the stuff’s right," he said. "When it’s under the gun, it sometimes can be a little different, but the results with the putter today, I couldn’t be happier.

"It actually made me smile, and I don’t smile much." 

Garnett finished part of the five-man group tied for third at four under, along with fellow strong putter Doug Ghim (2.90 strokes gained putting), while Tony Finau, Tom Hoge and Emiliano Grillo reached their score in a different fashion.

Grillo was solid all around without excelling in one area, while both Hoge (minus 0.73 strokes gained putting) and Finau (minus 0.56) struggled on the greens. 

However, they were the top two in the tee-to-green category, with Hoge at 6.62 strokes gained and Finau at 6.45, with Hank Lebioda a long way back in third at 4.97. 

Lebioda is one of nine players a further stroke back at three under – tied for eighth – along with Canada's Adam Hadwin and Sweden's David Lingmerth.

Taiwan's C.T. Pan and South Korea's Noh Seung-yul are part of the group at two under, while Australian trio Jason Day, Cam Davis and Greg Chalmers shot one-under 70s.

Recent PGA Tour winner J.T. Poston highlights the group at even par, with England's Danny Willett at one over, and Canada's Adam Svensson at two over.