BLAINE, Minn. – Richy Werenski birdied three of the last four holes Saturday to erase a four-stroke deficit and catch Michael Thompson for the 3M Open lead.

After sharing the halfway lead, Thompson and Werenski traveled on vastly different paths to each shoot 3-under 68 before walking together to the clubhouse even again. They were at 15 under at the TPC Twin Cities.

Charl Schwartzel shot a 66 in the third round, pulling even with Tony Finau for third place at 13 under. Max Homa posted a 64, making a big jump to fifth at 12 under.

Thompson, who entered the week well below the cut for the FedExCup Playoffs in 151st place, made three straight birdies on the front nine. The 35-year-old, whose only career PGA TOUR win was at the Honda Classic in Florida in 2013, knocked in another one on the 590-yard, par-5 12th hole to move to 16 under.

Thompson held a four-stroke lead until the 15th, when his game on the greens suddenly faltered. His 8-foot putt for birdie went long, and he settled for par.

Werenski, who was one spot off the FedExCup cut last season and came to Minnesota in 89th place, birdied the 15th hole to move up. So did their playing partner Finau, making up for three earlier bogeys.

Thompson rolled a 15-footer too long on the 17th green, too, taking just his second bogey of the entire tournament as a light rain began to fall on another muggy and breezy afternoon in this suburb north of Minneapolis as the heat index reached the upper 90s.

Thompson, whose best finish was a tie for eighth at the RBC Heritage in South Carolina, started 18th with even more trouble by hitting his drive into the drink. There were 248 balls hit into water hazards over Thursday and Friday, the most through two rounds on the PGA TOUR this season.

Thompson’s next try after the penalty stroke landed in the green-side bunker, but he saved par with a clutch chip out of the sand that landed 7 feet from the cup. Werenski, whose 63 in the first round is tied for the low score of the tournament, birdied that hole. That set up a Sunday duel with a handful of competitors well within striking distance.

That includes Schwartzel, the 35-year-old South African who has two career TOUR victories. He just missed an eagle on the 18th, when his 70-foot shot from the bunker almost dropped in.

“It was a slow motion lip-out,” Schwartzel said.

Homa, who missed the cut on four of his last five starts, had eight birdies.

“I guess it’s been, I don’t know, four or so months since I’ve been in any kind of heat other than the cut heat, so it was kind of nice to just keep doing what I was doing at the beginning of the season,” said Homa, who bogeyed the 17th.

Tringale made four birdies and an eagle over his first eight holes on the way to tying his career low score with a 63, last posted in 2011. He only needed 25 putts, giving himself an outside chance for his first tour win.

“Golf’s a game of confidence. I love where I’m at. I love where my game’s at,” Tringale said. “Sundays are a different day, so I’m excited about the opportunity.”