Michael Thompson and Richy Werenski stand strong atop 3M Open leaderboard

As skies darkened, winds gusted and raindrops fell, everything changed at the 3M Open in its final hour Saturday afternoon — and yet nothing did at all now that Friday co-leaders Michael Thompson and Richy Werenski still go to Sunday's final round tied, at 15 under par.

Gone by day's end was Thompson's four-shot lead with four holes left, lost on TPC Twin Cities' dangerous, watery par-3 17th hole and par-5 18th. He made only his second bogey in three days on 17, then saved par at 18 after he drove it into the lake enlarged before last year's inaugural tournament

Thompson still skillfully got up and down from a greenside bunker, celebrating a 7-foot par putt with a fist pump worthy of a victor.

"I'm honestly just proud of myself for stepping up," Thompson said.

Werenski, meanwhile, made three birdies in the final four holes to regain his share of a lead he has held all three days, making an 8-foot birdie putt to close at 18.

The two men lead world 17th-ranked Tony Finau and 2011 Masters champion Charl Schwartzel by two shots and 2019 Wells Fargo Championship winner Max Homa by three. Seven players — including multiple PGA Tour winners Ryan Moore, Harris English and Nick Watney — are four shots back, at 11 under.

Thompson, 35, has won the tour's Honda Classic in 2013 and the Web.com tour's Boise Open in 2016. Werenski, 28, has won once on the Korn Ferry Tour. Finau, 30, has played on Ryder Cup and Presidents Cup teams, finished top eight in all four majors, is 17th in the world and has been runner-up six times. But his only PGA Tour victory came at the 2016 Puerto Rico Open.

Thompson maintained a share of the lead after he took a penalty stroke and a drop after he hit into the water at No. 18 and still made par. Before he hit a 287-yard shot over water, caddie Damian Lopez simply told him, "Time to step up and play the game."

Thompson has held the 54-hole lead twice in his PGA Tour career. He didn't win the first time in 2011, but he held off Geoff Ogilvy and won the Honda seven long years ago.

"The biggest thing is remembering what it felt like to be in the last group, to have the feeling coming down the last holes where I truly believed I was going to win the tournament," Thompson said. "And I did. … The game, it doesn't need to be more complicated than it is. If I keep it simple, I'm going to have a good day."

Werenski went to bed Saturday having never been in this position on the PGA Tour, but he has held at least a share of the lead all three days in Blaine. He has had two runner-up finishes in his first 98 starts on tour.

He'll be paired again with Thompson, as he was Saturday when he finished with birdies at 15, 16 and 18 and made a big 6-foot par putt at 17.

A year ago, 20-year-old rookie Matthew Wolff made a 26-foot eagle putt from the fringe at the 18th to trump Bryson DeChambeau's own eagle there just minutes before and won his first tour title. This time around, 18 players, including Wolff himself, are within five shots of the lead.

"There's still a lot of golf yet," Werenski said. "I just want to keep hanging around and hopefully something happens."