Fox has won the Canadian Open in Toronto.
However, he and American Sam Burns went through four play-off holes before a winner could be found.
"It was a bit scratchy for 13 holes today but made a couple of good saves and kind of found it the last four or five holes (where) I hit some great shots," he said green side afterwards.
"Didn't hit a couple of great shots in the play-off and Sam let me off there.
"But it was nice to hit a good one on 18 that fourth time, that's probably the best shot I've ever hit in my life."
Fox struggled to explain what he's managed to achieve in the last month."I don't know, it's crazy the last four weeks, I've played some of the best golf I've ever played.
"To get a couple of wins on the PGA Tour in a month is pretty surreal."
Fox started the final round in a tie for the lead but slipped three shots off the pace at one stage before charging back into contention.
He birdied three of the last five holes to force the play-off.
Fox was lucky to survive the first play-off hole after putting his tee shot in a bunker, but Burns missed a very makeable putt to win.
Both players then parred the 18th on the second and third extra holes.
Burns then three putted, giving Fox two shots for the win and the NZ$2.95 million winner's prize.
The pair finished one shot ahead of Kevin Yu of Taiwan.
It was Fox's second play-off victory on the PGA Tour in less than a month.
He claimed his maiden PGA title with victory at the Myrtle Beach Classic in South Carolina after a three-way play-off.
The win qualifies Fox for this week's US Open in Pennsylvania, the third major of the year.
