Phil Mickelson admitted agonising over his decision to part with long time coach Rick Smith, but was left in no doubt he made the right choice after winning the Players Championship late last night.

In just his third event since firing Smith and opting for Butch Harmon, a polished Mickelson produced a near-flawless final round at the Sawgrass TPC to claim a two-shot victory over Sergio Garcia.

Driving the ball with the sort of accuracy he could only dream about barely a month ago, he missed only four fairways, while methodically plotting his way to a three-under-par 69 in ideal conditions in Florida.

Mickelson's swing changes with Harmon are a work in progress, but it must be a daunting prospect for his rivals to consider just how good he will be if he starts consistently finding the fairway with his drives.

"I'm excited about the way my ball-striking seemed to get better as the week went on," he said after finishing at 11-under 277. "I think if I keep working at these things and progressing, I should be ready to take on the ultimate tough challenge at Oakmont (site of the next month's US Open)."

Mickelson carded a final hole double bogey at last year's US Open, a blunder that handed the tournament to Australian Geoff Ogilvy.

Mickelson took time to get over that disappointment, but perhaps there was a silver lining in that he drove the ball so badly that week he started questioning his coaching situation.

But it wasn't until after a disappointing performance at last month's Masters that the 36-year-old Californian finally decided to leave Smith for Tiger Woods' former coach.

"I felt I hadn't hit it well since the Masters in 2006," he said. "When I got to Augusta and wasn't able to hit it well again after a year, I felt I needed to try something different."