Kisner, a six times runnerup on the PGA Tour, boldly slammed his uphill putt into the middle of the cup for his second career win.
“I’ve been in this position a ton and haven’t finished as much as I’d like to,” the intense 33-year-old from South Carolina told Golf Channel after carding 66 to finish at 10-under 270 at Colonial Country Club.
In closing the deal, Kisner avoided what would have been a four-way playoff, finishing a stroke clear of fellow Americans Jordan Spieth (65) and Sean O’Hair (66), and Spaniard Jon Rahm (66).
Rahm had the best chance to force extra holes but missed a 10-foot birdie putt at the last.
Overnight leader Webb Simpson (71) bogeyed the par-four 18th to finish two shots behind.
Kisner jump-started his round with a 40-foot birdie at the par-four 10th and then broke clear with further birdies at the next two holes.
But a three-putt bogey from the fringe at the 16th set up an exciting finish.
“I hung in there coming in,” he said. “It got a little tighter than I wanted to but it’s a fun way to finish. I kept going at the flag and trying to make as many birdies as I could.
“I’m just happy to win any tournament, but especially here. I love this place.”
Spieth came close to successfully defending his title with a bogey-free final round but left too much ground to make up.
“It was really close,” the former world number one told reporters. “All in all a very solid round. It’s hard to ask for much more than 65 on the last day."
Spieth was upbeat to find his form. On Friday he was in danger of missing an unprecedented third consecutive cut but he played the final 45 holes in 11-under.
Rahm, 22, continued to enhance his profile as the game’s next superstar with another stellar performance, breaking into the top 10 in the world rankings.
He had birdie putts inside 20 feet on the final eight holes but converted only two of them.
“I wish I could have made a couple more,” he said. “This is golf. I kept hitting good shots and having putts from 10 or 15 feet for birdie. It will sting for a little while.”
(Reporting by Andrew Both in Cary, North Carolina; Editing by Frank Pingue / Ian Ransom)
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