IRVING (AP) – When the local teenage amateur playing with Keegan Bradley hit an approach inside 5 feet on the 10th hole during the final round of the Byron Nelson Championship, there was a loud roar from the large gallery following their group.

Bradley then got his even closer.

“There was two claps,” said Bradley, who went on to his first PGA Tour victory.

Bradley’s last birdie of the day that got him to 3 under didn’t rouse much excitement from the crowd more interested in 17-year-old Jordan Spieth.

But the nephew of LPGA great Pat Bradley finished with eight consecutive pars after that on Sunday, then had to wait about an hour before winning a one-hole playoff over Ryan Palmer with a 2-foot par putt.

The PGA Tour rookie, a Vermont native and former St. John’s golfer who never even won on the Nationwide Tour, got his first professional victory nine days before his 25th birthday. Bradley’s aunt won 31 tournaments, including six majors.

“She is a lot calmer on the golf course than she is watching me. I’m sure she was by the TV going crazy,” Bradley said. “I talk to her regularly through text messages and phone calls about tournaments and what it’s like to come down near the end. … This is the closest thing we ever had in common in terms of playing.”

Bradley (68) and Palmer (72) finished 3-under 277, the highest final score on the PGA Tour this year and highest in relation to par in a non-major since 1999. It was the fifth playoff in six weeks and 10th overall.

Ryuji Imada and Joe Ogilvie (70) finished a stroke back at 2 under. Defending Nelson champion Jason Day (67) finished fifth at 1 under — the last player who finished under par this week at TPC Four Seasons.

There were brutal scoring conditions, particularly for both weekend rounds when the wind was sustained at 25 mph with gusts howling near 40.

When Bradley sank a 12-foot par-saving putt on No. 17, he responded with an emphatic fist pump. He dropped into a squat and hopped a few times in frustration when his 10-foot birdie chance at No. 18 slid by the hole.

Third-round leader Palmer and Imada were still among the five groups still playing when Bradley tapped in his first par putt at No. 18.

But the playoff almost wasn’t necessary for Bradley to become the PGA Tour’s sixth first-time winner this season.

Imada was 5 under after his 11-foot birdie putt trickled in at the 170-yard 13th, then blasted out of a greenside bunker to inside a foot at 14th to save par. But he bogeyed three of his last four holes, including a 3-foot par miss at No. 17.

Palmer shot from a greenside bunker to 3 feet for a birdie at the 523-yard 16th hole to get back to 3 under, but gave that stroke right back when he missed a 7-foot par at No. 17. There was only one birdie all day at No. 18 before Palmer sank a 6-footer to force the playoff.

“I knew as long as I kept grinding and grinding I could give myself a chance to win,” said Palmer, a Texas native who missed the cut in six of his first seven Nelson appearances. “I’m proud to come to a golf course I’ve struggled on and finish second, and also a little disappointed to lose a playoff.”

The playoff at No. 18 began with Bradley and Palmer both hitting their tee shots way right.

Tournament volunteers quickly dismantled and moved a temporary lemonade stand to give Bradley a line of sight to the green. His approach still came dangerously close to sliding off the side of the green into the water.

Palmer went in the same direction, but his ball got wet and he eventually made a 13-foot bogey.

Spieth was still in the top 10 before two double bogeys and two bogeys in his final four holes for a closing 77.

“I was humbled by this back nine,” Spieth said. “I’m focused on college now. Had I won today, who knows, but I’m focused now on the next step. This will sink in, and I’m sure it will sink in in a positive way.”

Spieth, who is going to the University of Texas this fall, made the Nelson cut for the second year in a row. He finished 6 over and tied for 32nd place, which was 10 strokes higher than last year when he was tied for 16th.

Only Day with 22 birdies had more than Spieth’s 20 this week. But Spieth, who missed his high school graduation ceremony Saturday because of the Nelson, also had 20 holes over par (14 bogeys, and six double bogeys).

Sergio Garcia, the 2004 Nelson champion who hasn’t won since 2008 and hasn’t locked up spots this year in the U.S. Open and British Open, began the day one stroke off the lead.

Garcia slammed his putter down on his bag after missing a 4-foot par putt the opening hole. Things only got worse in a closing 77, including a double-bogey 6 at No. 4 when he needed four shots to go the final 12 feet after a chip shot rolled back to his feet.

Day, the Masters’ runner-up this year, had his fourth top-10 finish in his past five tournaments. Before closing with consecutive pars, he was even over a stretch of seven holes without a par. There was a birdie at No. 10 before consecutive bogeys, a birdie, a double bogey and then consecutive birdies.

“If I didn’t make those mental errors on the back nine I would probably be sitting here at 4 under,” Day said. “But, hey, I played great today, and I’m not too disappointed.”

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