Palm Harbor, FL (SportsNetwork.com) - Jordan Spieth rolled in a bending, 28- foot birdie putt on the third playoff hole Sunday to defeat Patrick Reed and 2008 champion Sean O'Hair and win the Valspar Championship.

After hitting his tee shot on the green at the par-3 17th, Spieth watched as Reed and O'Hair failed to make birdie before rolling in his huge putt for the win. The trio finished regulation tied for the lead at 10-under-par 274.

Spieth, who now has two career victories on the PGA Tour, carded a 2-under 69 in the final round. Reed fired a 5-under 66, while O'Hair shot a 4-under 67 on the Copperhead Course at Innisbrook Golf & Spa Resort.

World No. 3 Henrik Stenson hung around throughout most of the day, but his 67 was not quite enough as he ended alone in fourth at 9-under 275.

Third-round leader Ryan Moore, who held a 3-shot lead with six holes to play, made three crucial bogeys down the stretch and was unable to make birdies when it mattered most. Moore shot a 1-over 72 and finished alone in fifth at minus-8.

After a wild finish to regulation play, Spieth, Reed and O'Hair went back to the par-4 18th for the first playoff hole. It was advantage Spieth to start as he hit his second shot to about 10 feet, while O'Hair found the back of the green and Reed hit a greenside bunker.

With an awkward shot out of sand, Reed scrambled for par and O'Hair 2-putted to match. Spieth's birdie putt just slid by and he made par, forcing a second extra hole.

Now on the par-4 16th, O'Hair was the only player to find the fairway as Reed and Spieth found the rough on the left side. This time it was advantage O'Hair as his approach stopped within 15 feet. Spieth found the back fringe and Reed hit his shot over the green and into the rough.

Reed's next shot got to within inches of the hole and Spieth missed his putt. O'Hair's putt for the win just lipped out and the trio headed to the par-3 17th for the third playoff hole.

"I hit the putt I wanted to hit. I mean I hit it right on my line. I thought I made it," said O'Hair. "I wanted it to go slightly to the left. Patrick's chip kind of veered off a little bit to the left, so did Jordan's putt and the grain was going that way, so it just wasn't meant to be. You know I hit a great putt there and I gave it my all. Jordan's a great champion."

For the second time in three holes, Reed found a bunker, while Spieth and O'Hair both hit the green. Reed blasted out of the sand and O'Hair missed his long birdie effort, giving Spieth another shot at the win.

This time the 21-year-old came through by dropping his birdie putt right in the middle of the cup for the victory.

"It was a crazy back nine being three down with six to play. That was the best Michael and I have ever done together," said Spieth of his caddie Michael Greller.

"And then I mean that putt (to win), that's just luck, right? I mean if that doesn't hit the hole, I've got a 4-foot slider, but I guess it was my day."

It was one of the crazier finishes to regulation play, which had Moore leading by three late. Moore, who held a 1-shot lead over Spieth entering the final round, birdied the first along with Spieth.

There was a 2-shot swing at the second as Spieth made birdie and Moore made bogey, giving Spieth the lead at minus-10. Moore then went on to bogey his second straight hole on three, dropping him two shots back.

In the meantime, O'Hair opened with four straight pars before making a birdie at the fifth to pull within three along with Stenson, who made gains on one and two.

While O'Hair dropped a shot on six to fall to minus-6, Spieth also bogeyed No. 5 and Moore was back within a shot.

Then came a huge swing as Moore holed out for eagle from 172 yards out on the par-4 sixth. Spieth made a mess of that hole and went on to bogey. Just like that, it was a 3-shot swing and gave Moore a 2-shot lead at 10-under.

Then Reed's name surfaced. Reed made nine straight pars from two after opening with a birdie at the first. He then rolled in a gain on 11, pulling him to within three.

Moore tripped to another bogey on 10, getting everyone behind him one shot closer. O'Hair birdied 11 and Reed made it back-to-back gains with another birdie on 12. With Moore at 9-under, Spieth and Reed were a shot back, with O'Hair right behind them two shots behind.

O'Hair made another gain on 12, tying him with Spieth and Reed. Stenson, who bogeyed No. 9, made a late charge starting with a birdie on 14, getting him up to 7-under.

Moore appeared to be in control when he rolled in back-to-back birdies on 11 and 12, giving him a 3-shot lead.

Then came another big swing as Moore tripped to a bogey on 13 and Spieth an 11-foot birdie on 13, pulling him within one.

The others decided to join the party as well, all almost simultaneously. Stenson made it three straight birdies with gains on 15 and 16, Reed rolled in a putt for birdie on 15 and O'Hair birdied 14, pulling them all even with Spieth and one behind Moore.

After Spieth holed a long 32-foot putt for birdie on 14 to join Moore at minus-10, O'Hair also made a gain on 16 to tie the lead.

Then it was Reed's turn to have a flair for the dramatic as his 31-foot birdie at the last fell. Just like that, with Stenson finishing at minus-9, there was a four-way tie for the lead at 10-under.

"I hit a softy eight in regulation and hit it just past the flag and hit a perfect putt, perfect speed to make it just to get myself in the playoff," Reed said about his putt on 18.

While the playoff trio held strong and were able to save some big pars down the stretch, Moore fell off with bogeys on 16 and 18 to finish two shots off the pace.

Spieth nearly missed out on the playoff, but he was able to scramble and make a 12-foot par putt at the last.

NOTES: Five of the last seven events on the PGA Tour have gone to a playoff ... Spieth's other win at the 2013 John Deere Classic was also in a playoff ... Spieth is only the fourth player since 1940 to win twice on the PGA Tour before turning 22 (Tiger Woods, Sergio Garcia, Robert Gamez) ... Both Reed and O'Hair were seeking their fifth win on tour ... Reed already has one win this year at the Hyundai Tournament of Champions ... With the win, Spieth earned $1.062 million ... The tour remains in Florida for the Arnold Palmer Invitational next week, where Matt Every outlasted Keegan Bradley for the title last year.