Lee Kyoung-hoon became back-to-back champion at the AT&T Byron Nelson after he posted a career-best 63 in Sunday's final round to finish 26 under for the tournament.

His 26 under was one stroke better than his winning score from a year ago, at 25 under.

He started his last round beautifully, registering back-to-back birdies on holes two and three, as well as five and six, with another on nine giving him a 31 on the front-nine.

Lee's biggest moment of the day came on the par-five 12th, where he put his second shot less than five feet from the pin for a comfortable eagle.

With the pairing of Jordan Spieth and Sebastian Munoz breathing down his neck, trailing by one stroke, Lee birdied the 18th to make it a two-stroke lead. 

It forced the chasers to play hyper-aggressive on the last with each needing an eagle to force a playoff, and Spieth could only birdie, claiming outright second place at 25 under.

Speaking to the media after his win was confirmed, Lee said it felt like a dream – again.

"It's so amazing," he said. "It's just like a dream, again, like last year. 

"With my family – my wife and daughter are here – it's amazing."

Munoz finished in a tie for third with Hideki Matsuyama, who shot a 62 to be one stroke off the round of the day, which was a 61 by Xander Schauffele.

Schauffele ended up in a tie for fifth at 23 under, but he was the leader in the clubhouse when he finished his round.

Also at 23 under were Schauffele's American compatriots Ryan Palmer and Justin Thomas, with Charl Schwartzel outright eighth at 22 under, while the group of Peter Malnati, Davis Riley, and James Hahn rounded out the top-10 one stroke further back.

Masters champion Scottie Scheffler was in the mix heading into Sunday's play, but could not keep up with the incredible scoring atop the leaderboard, finishing with a 69 to post a 19 under tournament score, tying him for 15th.

Adam Scott put together his best round of the week on Sunday with a 65 to finish at 16 under, as was the case with fellow Australian Jason Day, coming back from a 73 on Saturday to shoot 66 and finish 13 under.

After entering the final round in contention, Chile's Joaquin Neimann laid an egg, tying for the worst round of the day at 74.

The shot of the day came from Justin Lower, acing the par-three 17th to finish two under for the hole, and two under for his round, back in a tie for 46th.