NORTON, Mass. — Kevin Chappell made six birdies and an eagle Saturday and wound up with the 36-hole lead at the Deutsche Bank Championship.

Nothing brought out more emotion than his only bogey.

Chappell missed the green well to the right on the 13th hole and with a far right pin, he didn’t have much of a shot. He tried to chip it up the hill, only it came up short. He tried a flop that didn’t quite stay on the green. And all he could think about was last week at Bethpage Black.

Chappell was in reasonable shape late in the second round at The Barclays when he finished bogey-double bogey-bogey. Instead of being one shot behind, he dropped four shots in three holes. At the TPC Boston, he wondered if he was headed down the same road.

Not this time. Chappell holed the 15-foot bogey putt, added two birdies and closed out a 7-under 64 for a one-shot lead at the halfway point.

“I was fighting some internal demons there,” Chappell said. “I couldn’t help but recall the same situation last Friday. To know that, refer to it and then not let it happen again is huge, and that’s why you saw the emotion from me.”

He was at 11-under 131, one shot ahead of PGA champion Jimmy Walker (64) and Paul Casey (66).

Dustin Johnson was poised to join Chappell in the lead until his long iron on the 18th sailed well right into the trees. He had to take a penalty drop, hit wedge on to about 45 feet and then three-putted for a double bogey. He still shot 66 and was three behind.

At least he still has a chance.

Phil Mickelson missed the cut for only the second time in a FedEx Cup playoff event, making a double bogey on his final hole for a 72. Jason Day, the world No. 1, took a quadruple-bogey 8 on the fifth hole and rallied to make the cut on the number.

The cut was at 1-under 141.

Also missing the cut was Bubba Watson, still hopeful of a captain’s pick for the Ryder Cup. Justin Thomas also is trying to make a case, and Saturday didn’t help the cause. His good start was wasted by a 40 on the back nine, which included two balls in the water for a triple bogey on the par-3 16th, and he wound up missing the cut.

Chappell nearly threw away a shot at the end. After a good drive on the 18th, he watched players in the group ahead struggle from the left of the green. Chappell figured his best chance was to lay up, but he hit it weak, the ball caught a gust of wind and it landed in the thick collar of a pot bunker.

His next shot made up for it, a wedge that jumped on him but still had enough height to settle about 15 feet away for par.

Chappell already has three runner-up finishes this summer (two of them to Day). He is patient about his prospect for that first PGA Tour victory, and it helps that he’s having a career season. At No. 13 in the FedEx Cup, he is all but set to reach the Tour Championship for the first time.

“It’s hard to be frustrated when you’re having the best year of your career,” he said. “That’s really how I try to look at it. … I would love to have won, and won multiple times, but I’ve learned from those experiences. You don’t know if you’re improving until you get in the situation and see how you hold up, so look forward to that.”

Casey is at No. 59 in the FedEx Cup, needing a good week to make sure he stays in the top 70 to advance to the third playoff event at the BMW Championship next week. That shouldn’t be a problem. He played bogey-free for a 66 to get in the last group with Chappell.

Brian Harman is at No. 67 in the Fed Ex Cup. He had a 65 and was two shots behind. Joining Johnson at 8-under 134 was Smylie Kaufman, who had reason to expect so much more than his 66. Kaufman was 7 under through seven holes, thanks to a chip-in and an eagle. But he closed out the front nine with bogeys, and played even par on the back nine.

Walker recovered from his malaise after winning his first major at Baltusrol. He missed the cut in his next two weeks, but spent time at home working on his game and appears to have returned to form. He finished strong with an eagle on the par-5 seventh and a birdie from the first cut of rough on the ninth hole.

Thirteen players who were at No. 70 or lower in the FedEx Cup missed the cut, meaning their season is over. That group includes Webb Simpson and Vijay Singh.