Kevin Na powered to a four-shot win at the Charles Schwab Challenge to secure his third PGA Tour victory om Sunday.

The South Korean-born American shot a final round four-under-par 66 to finish on 13-under to take the title at Colonial ahead of second placed Tony Finau.

Na started the day in the lead and made a statement of intent early on in the final group as he made three birdies over the opening six holes.

And with the win all-but secured coming down 18, Na finished in style to birdie the final hole to record his third victory on the American circuit.

Na's final round was only bettered by Scotland's Russell Knox who shot five under to move into a tie for eighth place, while Jordan Spieth failed to challenge and went down the leaderboard following a disappointing two over par 72.

American Andrew Putnam and CT Pan from Taiwan finished joint third on eight under par, five shots behind the winner.

Graeme McDowell finished last of those to make the weekend in 73rd position on 12 over following a final round 72.