ZACH Johnson has won the 144th open championship at St Andrews in a thrilling four-hole playoff.

The tournament went to four-hole play-off (1,2,17,18) with Aussie Marc Leishman, Zach Johnson and South African Louis Oosthuizen – the champion here in 2010 – after the trio finished 72 holes at 15-under par.

The 2007 Masters champ added the Claret Jug to his green jacket after finishing with the four holes at 1-under, while Oosthuizen finished even and Leishman 2-over.

Fellow Aussie Jason Day and playing partner Jordan Spieth just missed out, finishing at 14-under.

On the first hole, Oosthuizen and Johnson holed their putts for birdie while Leishman three-putted for bogey after his tee shot unfortunately found a sand-filled divot.

Johnson birdied the second extra hole to take a one-shot lead , while Oosthuizen and Leishman recorded pars on the second extra hole.

On 17, Oosthuizen, Leishman and Johnson all bogeyed.

Johnson then took a one-shot lead into 18 where the trio recorded pars.