CROMWELL — What was looking like a nice stroll around the TPC River Highlands golf course Saturday afternoon turned into a disaster very quickly for Zack Sucher.

The journeyman pro blistered the front nine with five birdies, opening up a five-stroke lead. Then the fun began with his tee shot on 10. Within 40 minutes, the lead was gone.

Chez Reavie took control and stretched the lead from there. Reavie has a record six-shot lead over Keegan Bradley and Sucher after shooting a 63 and a record-tying 28 on the back nine.

“I have shot 28 before on nine holes, but not on tour, I don't believe. I've done it at home,” Reavie said. “If I go out and shoot 5 or 6-under tomorrow, if someone catches me they're going to play a hell of a round. That's my goal. Go shoot 5 or 6-under par tomorrow.”

It’s the largest 54-hole lead in the 68-year history of the tournament. The previous record was four strokes held by four people. Three of those leads were at Wethersfield CC — where the tournament was held through 1983 — including Sammy Snead in 1955.

The only one at the present course was Paul Casey last year — and he is the only one to not hang on to win.

“Tomorrow I'll be nervous, just as I was nervous today and nervous last week,” Reavie said. “I think I've been in the heat a lot more the last few years, so I kind of know how to deal with my nerves a little bit better.”

Said Bradley: “It's going to take a low one and some help from him. He's a great player, so going to have to shoot something pretty low.”

Reavie, who finished tied for third at last week’s U.S. Open, will play with Bradley in the final group at 2 p.m. He has never been in contention before at the Travelers in eight previous trips. His best finish is a tie for 11th in 2012.

Reavie is searching for his first victory since the 2008 RBC Canadian Open.

Jason Day and Roberto Diaz are tied for fourth place at 9-under. Bryson DeChambeau and Tommy Fleetwood lead a four-way tie for sixth at 8-under. But it’s going to take a big round to catch Reavie.

“Yeah, that margin can dwindle pretty quickly, especially around a golf course like this. If we get some tough breezes tomorrow, northwesterly, it's going to set up for some good golf, I think,” Day said. “I'm excited about the chance to go out and try and win tomorrow.”

Sucher, in the midst of a Major Medical Extension after ankle surgery cut short his 2017 campaign on the PGA Tour, birdied three of the first four holes. He added a birdie on 8.

And then Sucher, ranked 505th in world and 222nd in the FedExCup rankings, completely unraveled. His drive on 10 traveled just 154 yards, leading to a bogey.

“No. 10 was awful. I deserved a bogey,” Sucher said. “That’s the worst swing I’ve made in awhile.”

He buried his tee shot in the bunker on the downhill par-3 11th and left it in on his next shot. That led to a double-bogey and the lead was down to 1 in 20 minutes.

His approach on the 12th hole was left of the bunker. His next shot hit on the hill and went back down into the bunker, leading to another double bogey. Sucher’s lead was gone.

Reavie, who birdied holes 10 thru 12 playing alongside Sucher, now led Bradley by one and Sucher by two.

“He hit a bad tee shot on 10, but his tee shot on 11 wasn't terrible. The wind just kind of blew it over there and then he was plugged in the bunker. Really tough break,” Reavie said. “It was tough to watch because he didn't really hit that bad of golf shots. I was picking my lines and trying to avoid the bunkers.”

Said Sucher: “It was rough, that’s all you can say about it. … Other than those three holes, it was a great day.”

It ended up being an eight-shot swing between Reavie and Sucher in those three holes.

“The front nine, I hit my driver awesome,” Sucher said. “The back nine, I wasn’t as good with it and I paid for it.”

Reavie extended the lead with a fourth straight birdie on 13, getting up and down from the bunker behind the green on the par-5 hole.

Another birdie at 15, a hole Bradley bogeyed after hitting his tee shot in the water, and Reavie’s lead was four. Then he birdied 17 and 18.

“I was definitely drained on Monday and Tuesday after last week, but now it's tournament time. There is no time to be tired. I'll go get some rest tonight and be ready to go,” Reavie said.

joseph.morelli

@hearstmediact.com; @nhrJoeMorelli