Stenson was among the early starters on Friday and overcame the combination of occasional downpours and a change in wind direction to card a superb 65 to lie just a shot behind 2013 champion Phil Mickelson.
“I think I timed it quite well,” Stenson said after carding seven birdies and a solitary bogey in his lowest Open round by two shots. “It was quite playable the first five holes before the rain hit the first time and I managed to pick up birdies on three, four and five.
“Then it eased off and I birdied another one on seven. The only bogey was a bit of a soft one; I missed the second shot right on nine and didn’t get up and down. Then the fun really started. It was blowing a bit more and starting to rain quite heavily and I birdied 10 in those conditions.
“Then I was hanging on for dear life on 11 and 12 really. They were playing tough and I got away with a couple of pars and then finished up quite tidy with another couple of birdies on the way home.”
Stenson finished second to Mickelson three years ago at Muirfield and, after turning 40 in April, admits time is running out in his bid to become the first male Swedish player to win a major.
“I haven’t been in contention for the last six majors and it was a big, big goal of mine to try and be up there and give myself a chance – so far, so good,” added the world No 6, who had recorded 13 top-four finishes without a victory before claiming his first win since November 2014 in the BMW International Open in Germany last month.
“I just wanted to turn things around because I’m not going to play these tournaments forever and ever.
“I don’t have another 50 goes at them. It might be a dozen or 15 in total.”