Hideki Matsuyama set the early pace alongside two others at the Memorial Tournament, while star duo Rory McIlroy and Jordan Spieth made slow starts.
Matsuyama – the 2014 champion – carded a seven-under-par 65 to earn a one-stroke lead with Mexican Abraham Ancer and Chile's Joaquin Niemann after Thursday's opening round at Muirfield Village Golf Club.
There was a stumble from Matsuyama following a flawless front nine as the five-time PGA Tour winner dropped consecutive shots after the turn, however, the Japanese golfer reeled off four successive birdies from the 13th hole before eagling the 17th to claim a share of the lead.
Beau Hossler ended the day a shot behind, with Jamie Lovemark, Grayson Murray, Kyle Stanley and Lucas Glover five under heading into Friday's second round in Dublin, Ohio.
However, it was a mixed day for golf's star players as former world number one Jason Day only dropped one shot to be tied for ninth and within three strokes of the leading trio.
Masters champion Patrick Reed holed two birdies and a bogey for a first-round 71 to be one under alongside the likes of Justin Rose, Bubba Watson and 2013 winner Matt Kuchar.
Tiger Woods, world number one Justin Thomas, Dustin Johnson and Rickie Fowler closed the round even par in a difficult opening to their campaigns.
A five-time champion at Muirfield, Woods struggled early as he bogeyed his second hole before double-bogeying the 15th having hit his tee shot out bounds and the American dropped another shot at the next hole.
The 14-time major winner turned in three-over 39 heading to the front nine, however, Woods rallied by birdieing four of his nine holes to be tied for 47th.
It was far worse for Northern Ireland's McIlroy and American Spieth, who recorded rounds of 74 and 75 respectively.
Inconsistency plagued McIlroy after the four-time major champion – who finished second at last week's BMW Championship – found the water three times to be eight shots off the pace.
As for Spieth, he hit seven of 14 fairways and 12 of 18 greens in regulation but still found himself three over at the end of play.