At the height of his powers, few were as consistently competitive in the U.S. Open as Jason Day. In the mid-2010s, while racking up top-10 after top-10, he relished the fairways-and-greens test of golf’s toughest major. The grind for pars. The mental examination.

Friday at the Wells Fargo Championship might not have had the same stakes, but it presented a similar challenge.

For 5 ½ hours, players at TPC Potomac were drenched with a steady rain, turning what was already a difficult track into all they could handle. Among the early leaders, Day navigated that test the best, turning in a stout 67 to take a three-shot lead into the weekend. He is at 10-under 130.

“I’ve always liked U.S. Open formats in regard to how tough the golf course is,” he said afterward. “You have to grind it out. When you have tough conditions, long golf courses, thick rough, the guys that are playing well, they usually find their way to the top.”

And that’s exactly what Day has done as he continues his resurgent play.

The former world No. 1, who has been plagued by back problems over the past several years, is back where he believes he belongs, looking for his first PGA Tour title since this event in 2018, when he won at Quail Hollow.

“It’s nice to be back in the mix, nice to be leading,” he said. “It’s still two more days left, so I can’t get too far ahead of myself.”

Particularly with the weather forecast calling for even more rain – and perhaps heavier – over the weekend. So drenched was Day on Friday that he abandoned his hat midway through the round.

“Not many times you see this hair,” he said, but Day wanted to eliminate as many potential distractions as possible. One of his fellow playing competitors, Max Homa, told Day that he rocketed a putt past the hole because he flinched when a water droplet hit his putter on his backswing.

“Jason and I have been talking about it for like two and a half hours,” Homa said post-round, “that we can’t wait for it to be done and kick our feet up.”

Though annoying, the sloppy conditions didn’t seem to affect Day, who wore out his 4- and 5-irons but still added five more birdies Friday after an opening 63, the first time in six years that he’d started a tournament that low. Day recently played well in the team format at the Zurich Classic and seemed to be finding his form after a limited start to the year. He challenged at another tough track, Torrey Pines, for the Farmers Insurance Open, but he’s played only four stroke-play events since while grieving the loss of his mother, Dening, who died in March after a lengthy illness. Day has dropped to No. 127 in the world, well outside the qualifying cutoff for the upcoming U.S. Open.

“I lost a little bit of momentum,” he said. “But finally finding my footing again is nice.”

Through two waterlogged rounds, Day tops the field in strokes gained: tee to green. If that holds through the end of the tournament, it’d be the first time since September 2015 that he led that statistic.

“I’ve just got to try and be as patient as possible,” he said. “I feel like the swing itself is in a nice spot, just be patient with it and go out and try to hit the ball and find it again. I’d like to say hit every green, hit every fairway, but that’s just not doable here.”