"We're competitors," Kuchar said. "We each want to win. You kind of forget that it isn't for the championship."
Kuchar earned $600,000, and Watson made $490,000.
Watson won the par-5 second with a birdie. Kuchar tied it with a par on the par-3 third, won the par-4 fifth with a par and took the par-4 ninth with a birdie.
They halved the next six holes, and Watson won the par-3 16th with a par. Kuchar then ended the match by winning the par-4 17th with a birdie.
In Saturday's semifinals, eventual champion Luke Donald beat Kuchar 6 and 5, and Martin Kaymer edged Watson 1 up.
Kuchar will move to No. 10 in the world ranking today. He jumped from 62nd to 13th last season.
SAND SAVE: Donald saved par with a deft 70-foot shot from a sandy waste area short of the 10th green to avoid falling behind for the first time in the tournament.
After Kaymer won Nos. 6, 8 and 9 to tie the championship match, Donald blasted out to 3 feet on No. 10 to set up a conceded par and a halve. Donald then won the 11th and 12th holes and went on to finish off Kaymer 3 and 2.
"I think that up and down on 10 was a huge point for me," Donald said. "If I'd gotten 1 down, I think that changes my mindset a little bit, my psyche. And I got it up and down and then, obviously, birdied three of the next six holes or so. I still felt pretty positive, because I still wasn't down in the match."
Donald relies on his short game.
"I know that my game off the tee and some of my iron play, there is room for improvement, you look at my statistics," Donald said. "But I make up for it around the greens, especially the last few years. And I pride myself having good fundamentals and working on it. And I can only thank my coach, Pat Goss , for that. We work hard on it."
SNOWBALL: Waking up to a snow-covered course before the championship match against Donald brought back some childhood memories for Kaymer.
"My parents, they took my brother and me out in the wintertime around Christmastime and we played in the snow with some pink golf balls or orange golf balls," Kaymer said.
"... It was definitely the toughest day from all of the last five days.".