After an opening 1-over 71, Stenson found the fairway on the 10th hole, his first of the day, then proceeded to hole a wedge from 108 yards for an opening eagle.
He followed that with a birdie on No. 11, and Stenson went on to card a 4-under 66 that served as the low round of the morning wave at Firestone Country Club.
“I’m very happy with the score,” said Stenson, who at 3 under trails Justin Rose by five shots through two rounds.
The highlight of the round was his second swing of the day, a three-quarter wedge that found the hole after Stenson said he “sniffed the flagstick” on No. 10 during the first round.
“That kind of set off the day,” he said. “The pitch mark was right on line. I don’t know if it jumped past and then spun back in, but it kind of sounded like that on the (crowd) reaction.”
Stenson was a runner-up here last year, but that remains his lone top-10 finish in seven prior trips to Firestone. While he admits that his track record at this event is not the best, he feels the tree-lined fairways of the South Course set up well for his style of play.
“It’s a course that should suit me pretty well if I’m playing good,” he said. “It’s fairly long, got to be accurate off the tee and get some longer shots into the green. It’s a course that I probably should have done better at in the past.”