WASHINGTON (AFP) — Wyndham Clark outclassed reigning Olympic champion Xander Schauffele in a back-nine battle on Sunday to win the Wells Fargo Championship by four strokes for his first career PGA Tour triumph.

The 29-year-old American fired a three-under-par 68 to complete 72 holes on 19-under 265 at Quail Hollow in Charlotte, North Carolina and defeat fifth-ranked Schauffele, who shot 70 to finish on 269.

"I'm a little choked up," Clark said as he fought back tears.

"It has been a long five years to get to this point on tour. I thought I would have had one earlier but it was well worth the wait. I'm just so grateful."

I'm a little choked up.

Clark won the $3.6-million top prize at the $20 million event, surpassing his prior best PGA payday of $485,000.

His PGA victory fulfilled a dream he had shared with his late mother, who died of cancer while Clark was in college.

"My mom, obviously, is not here," he said.

"I wish she was, but I know she's watching."

England's Tyrrell Hatton and American Harris English shared a distant third on 272 with England's Tommy Fleetwood and Australia's Adam Scott, the 2013 Masters champion, another stroke adrift.