Jason Day overcame rainy conditions in round two of the Wells Fargo Championship to take a three-shot lead into the weekend.
The Aussie, who won this event in 2018, pieced together a 3-under-par 67 to reach 10-under 130 after 36 holes on a day when the skies opened and scores ballooned.
"I've always kind of liked US Open formats in regards to how tough the golf course is. You kind of have to grind it out," said Day later.
The former World No.1 and 2015 PGA Championship winner is three clear of Max Homa, who fired a 4-under 66.
Torrey Pines champion Luke List (66), James Hahn (68), Kurt Kitayama (67) and Denny McCarthy (69) are all a further shot back on 6-under.
But Rory McIlroy's hopes of challenging for silverware ahead of the PGA Championship later this month were derailed by a 73 which dropped him 10 off the pace.
That's right on the cut line although he famously came from there to storm through the field and win here in 2010, shooting 66-62 over his last 36 holes.
Conditions at TPC Potomac are expected to remain challenging over the weekend with temperatures dropping further. The high on Friday was 63 degrees.
The anticipated inclement weather means third-round tee times will feature threesomes hitting off both No.1 and No.10 between 10.50am and 12.40pm.
The Wells Fargo Championship (also known as Wachovia and Quail Hollow Championship) was first played for in 2003 and Tiger Woods in 2007 is the only halfway leader to go on and win.
Three of the last five Wells Fargo Championship winners - Day (2018), Hahn (2016) and Homa (2019) are tied third or better going into the weekend.
This is Day's 15th halfway lead on the PGA Tour. He's managed to convert just three - the 2016 Players Championship, the 2016 Arnold Palmer Invitational and the 2015 BMW Championship. He actually went wire-to-wire in all those events.
Day ranks 1st for both Strokes Gained: Tee To Green and SG: Approach so far. He's 10th for SG: Putting.
Day has made 13 birdies (T1st) in his first 36 holes.
A look at what the leading contenders said after round two...
Jason Day (67, -10)
"I'm coming off some nice play at Zurich (10th), so I've got some confidence there. It's nice to be able to get in at 10 under through two rounds, especially with what kind of weather we've got coming in on the weekend.
"I'm looking forward to it. It's nice to be back in the mix, nice to be leading. It's still two more days left, so I can't get too far ahead of myself. I've just got to try and be as patient as possible. I feel like the swing itself is in a nice spot."
Max Homa (66, -7)
"I thought I played awesome for two days. Yesterday I played a really great round of golf and messed it up with probably just a bad decision off the tee and then a few bad shots in a row. But I've played great.
"I've hit the ball really well, I've hit my driver well, I've hit my irons great, I've made a ton of putts the last 27 holes. When I've been in trouble, I've kind of managed for the most part to get myself out of it. Yeah, I'm proud of the start, for sure. The game feels really good."
Luke List (66, -6)
"Anytime it's raining constantly like that for an extended period, it's challenging to stay dry and just stay patient. It's tough to get around this golf course anyway, but add that element of cold and rain, it was challenging out there.
"Yeah, 4 under on this golf course, I'll take it. Sunshine or no wind, doesn't matter any conditions, 4 under on this golf course is a good score. So to do it today was a testament to be able to keep my emotions in check and made some nice swings out there."
James Hahn (68, -6)
"Solid. Hit a lot of good shots today, played smart, made a lot of good putts. Didn't really make too many mistakes mentally and anytime you're doing that, whether it's a rainy day like today or sunny and 80 degrees, I feel like you're doing a good thing.
"I grew up in this stuff. This is kind of the reason why I left California is because of weather like this. It seemed like the year that I left, it was raining 100 days out of the year and so I would practice in this every day. So I feel comfortable. It kind of brings me back to the good old days when I was young and carefree and just wanted to go out and play golf."
Denny McCarthy (69, -6)
"I think this is where kind of my prep Sunday through Wednesday really helped. I didn't have my best stuff today at all. I didn't really hit it that great, but I put it in the right spots to let myself get it up and down, manageable up-and-downs, and I had a nice putter for most of the day.
"Hung in there and just shooting under par today feels pretty good since I didn't have my best stuff."
Some Rory magic
11th causes chaos
Power lip out!
Luke's hole-out eagle