(Reuters) - American Webb Simpson proved he has made a smooth transition to a regular-length putter after shooting an eight-under-par 62 for a share of the Sony Open first round lead with Englishman Paul Casey in Hawaii on Thursday.
Simpson recently abandoned the belly putter he had used for a decade ahead of the new regulation banning players from anchoring the club from next year.
In just his second event with the shorter 'flatstick', the 2012 U.S. Open champion needed only 10 putts on his inward half as he charged home in 28 strokes at Waialae in Honolulu.
Simpson told Golf Channel he wanted to get used to the shorter putter before the regulation came into force.
"I didn't want to wait until 2016 because I didn't want to be in a position where I felt like I was forced to the short putter," he said. "I was really nervous starting the day with the short putter."
He was even par after eight holes before picking up eight birdies in his final 10 holes.
Simpson and Casey both carded career-best scores on the PGA Tour to head Columbian Camilo Villegas and American Robert Streb by one stroke on a day when 69 players, nearly half the field, broke par in ideal conditions.
Defending champion Jimmy Walker shot 66, only three days after losing a playoff at the Tournament of Champions on the nearby island of Maui.
Arizona-based Casey, who has quit the European Tour to focus on playing in the United States, made his move with five consecutive birdies around the turn and the former world number three could hardly have wished for a better start to his year.
"It was a very tough decision," said Casey, whose 15 worldwide victories include one win on the PGA Tour.
"As long as I've been a professional I've been a member of the European Tour. Not being in the top 50 (in the world rankings), it's really difficult to play both tours.
"I fully commit this year to playing the PGA Tour. I'm excited about that. I can spend a little more time at home, come to great places like Hawaii and give it all I've got."