''It was tough out there,'' Reed said.
Finally resembling the guy who talked Saturday about being in a ''putting coma,'' Reed ran in an 18-footer for birdie on the par-3 15th to push his advantage to three strokes and parred the final three holes. He completed the wire-to-wire victory at 28-under 260.
''I started toward the end playing for par, just because I knew pars weren't going to hurt me,'' Reed said. ''I knew someone was going to have to do something spectacular to catch me.''
The 23-year-old Reed has two victories in his first 46 PGA Tour starts, winning the Wyndham Championship in August. He was projected to jump from 73rd to 42nd in the world ranking, enough to lock up a spot next month in the 64-man Match Play Championship field.
Palmer made a 15-foot eagle putt on the final hole for a 63.
''What can you do with what Patrick did this week?'' Palmer said. ''It's ridiculous what he did. Amazing how good he played. We'll come up a couple short, but it was a win in my game because I was playing for second today.''
''I got red hot at the end,'' Johnson said. ''I played really good early, missed a couple putts, but I made a bunch at the end.''
The Kapalua winner is taking a four-week break. He'll return for the Match Play event in Arizona.
''I know it's a necessity, I know it's good for me, it's good for my family, but I'm also hesitant because I'm playing well,'' Johnson said. ''Hopefully, I can maintain where I'm at. Maintain my posture and my fundamentals, and that sort of thing, and come back out here in Tucson ready to go.''
Leonard parred his last two for a 65.
''It's a great week,'' Leonard said. ''Would love to have made a few more putts today, but it's such a fun journey. I'm cutting my schedule back this year and all this does is kind of free me up to do that.''
Other than key 18-footer on No. 15, the longest putt Reed holed was a 5-footer for a par save on the par-4 13th. That also was a crucial putt after he played the previous eight holes in 1 over with four bogeys, three birdies and a par.
In that eight-hole stretch, Todd missed two 6-foot par putts and an 8-footer and dropped another stroke with a poor bunker shot on the par-3 12th. He two-putted for birdie on two par 5s and made a 4-footer on the par-4 eighth for the other birdie.
Reed also two-putted from 12 feet for a birdie on the par-5 second hole, but his eagle putt near had a chance - signaling that his putter had cooled off overnight.
''To come out and not have my full game and to have that much of a cushion to be able to just coast in, that's a good feeling,'' Reed said.
On Saturday, Reed broke the PGA Tour record for relation to par for the first 54 holes, finishing at 27 under. He also became the first player in tour history to open with three rounds of 63 or better.
Reed's wife, Justine, is pregnant with their first child, forcing her to turn over caddying duties to her brother, Kessler Karain. She has walked every hole this year and plans to caddie again after the baby arrives around Memorial Day.
After helping Augusta State win NCAA titles in 2010 and 2011, Reed drew attention in 2012 when he successfully Monday-qualified for six events and made 12 starts. The former Baton Rouge, La., high school champion earned his PGA Tour card in December 2012, surviving six rounds of Q-school at PGA West.