PHIL MICKELSON birdied the 16th and 17th holes in Akron, Ohio yesterday to complete a par 70 final round and win his fourth PGA title of the year, capturing the World Series of Golf.

The American finished at six-under par 274 to win his ninth career crown, defeating the second place trio of Billy Mayfair, Duffy Waldorf and Steve Stricker by three strokes.

Mickelson won $378,000 at the $2.1 million event, boosting the 26-year-old left-hander's season total to a US tour-leading $1.574 million.

Two bogeys by Mickelson dropped him into a tie with playing partner Mayfair entering the 16th hole. But strong approaches on the next two holes set up birdies while Mayfair made bogeys on the final two holes.