MAUI - Zach Johnson won the Tournament of Champions after rolling in seven birdies en route to a bogey-free 66 in the final round at Kapalua Resort on Monday. The 37-year-old American tied Billy Horschel for the low round of the day to win the USPGA Tour tournament by one shot. "Today was a grind but I felt at ease," Johnson said. "I was comfortable. Yesterday, I didn't score that well. Today I just tried to stay unemotional and remain athletic."Jordan Spieth, who is the reigning Tour rookie of the year, shot 69 and took second place at 18-under 274. Spieth shared the overnight lead with Dustin Johnson and Webb Simpson. Zach Johnson finished the event at 19-under-par 273 and earn his 11th USPGA Tour title. Johnson said his putting was the key. "I hit some quality shots that helped and some quality putts that helped even more," Johnson said. "What I have learned when I am in contention, and I haven't come through, it is because I am not doing what I was doing to get in contention. So the key is to just keep doing what you are doing."Former US Open winner Simpson carded a 70 and tied for third at minus-17. He finished alongside Kevin Streelman, who birdied four of his last five holes for a final-round 67. Jason Dufner (69) grabbed fifth at 15-under, while Dustin Johnson (73), Adam Scott (69), Matt Kuchar (67) and Horschel shared sixth at minus-14. Dustin Johnson, last year's champion, mixed five bogeys and five birdies during the final round.Spieth also had a bogey-free round Monday that included four birdies. He closed with consecutive birdies on 17 and 18. "I want to put myself in these positions because it was fun today," said Spieth, who is one of 13 first time winners from 2013 that competed in the event. "It is fun to feel the pressure and put your name beside some of the best players in the world on the leaderboard."I take away a lot of positives. This is the first time I have slept on a 54-hole lead. My putter just didn't hold up. It got a little cold on me. But it was a great experience feeling the nerves and battling," said Spieth who placed 17th at the World Golf Championships-HSBC Champions in his only other start of the 2013-14 season. His first career victory came at the John Deere Classic and he went on to post nine top 10 finishes last year.The Kapalua event, which is comprised of the winners from the previous season, was the first tournament on the USPGA Tour after an extended break. Because of the Tour's new wraparound schedule it is also the seventh event of the 2013-14 season. The Tour remains in the Aloha State next week for the Sony Open in Hawaii, which Russell Henley won in 2013.