The Europeans started fast, taking a one-up lead after the first hole. Johnson struck at the third to level the scores.
Dufner missed a putt at the fourth, and Westwood stepped up to show him how it's done by restoring their lead.
However, Dufner made up for his error at the ninth by holing a putt that clung onto the edge of the hole for an eternity.
The Americans then took a stranglehold on the contest, establishing a three-hole lead by the time the players reached the 16th tee.
Westwood stood over a four-foot putt on the 16th, but could not find the bottom of the cup and Johnson rolled in from mere inches for the win.