Collin Morikawa revelled in an "amazing" victory after winning the US PGA Championship on Sunday.

The 23-year-old American became the third youngest player to win the tournament since 1946 thanks to a thrilling victory at TPC Harding Park in San Francisco.

Morikawa fired a six-under 64 in the final round to secure a two-stroke victory ahead of Dustin Johnson and Paul Casey.

"It's amazing. It's been a life goal, obviously as a little kid, kind of watching everyone grow up, all these professionals, and this is always what I've wanted to do," he said at the trophy presentation.

"I felt very comfortable from the start. As an amateur, junior golfer, turning professional last year, but to finally close it off and come out here in San Francisco, pretty much my second home where I spent the last four years, is pretty special."

Morikawa produced some late magic with a chip in for birdie at the 14th before an eagle at the par-four 16th after an incredible tee shot.

The tee shot at 16 reminded Morikawa of a similar one at the Workday Charity Open last month, when he won his second PGA Tour title.

"[Fourteen] at Muirfield is pretty special, and my caddie looked at me after I hit my shot on 16 tee and asked me the same exact question. It just fit my eye," he said.

"We were just hoping for a really good bounce, and we got it, hit a really good putt, and now we're here."