Zach Johnson defeated Louis Oosthuizen and Marc Leishman in a four-hole play-off to claim his second major title in a thrilling conclusion to The Open at St Andrews.

Johnson, Oosthuizen and Leishman ultimately emerged as the pick of the field following a dramatic final round - played on Monday for the first time since 1988 following weather-induced delays - that featured numerous swings in momentum.

The decisive play-off so nearly featured Jordan Spieth, who was left to rue a four-putt double bogey on the eighth and a dropped shot on the famous Road Hole as he finished one shy of the leaders on 14 under.

Spieth was therefore unable to become only the second man, after Ben Hogan, to win the Masters, U.S. Open and The Open in the same year, and it was Johnson - the 2007 champion at Augusta - who prevailed after backing up a superb 66 in regulation play.

Johnson held a superb curling birdie putt on 18 to force his way into the shootout and then seized the initiative with threes on the first and second - putting him one clear of Oosthuizen and three ahead of Leishman, who started with a bogey.

A bogey on 17 followed for Johnson, but Oosthuizen - who began the day as one of three joint-leaders - and Leishman also made five, and the South African missed a 10-footer on the 18th that would have extended the contest still further.

Johnson, who will move up from 25th in the world rankings, had earlier surged to the top of the leaderboard with seven birdies in his first 12 holes on Monday.

After dropping shots on 13 and 17, he showed tremendous resolve to get back to 15 under with a three on 18 - and a score of one under for the four play-off holes proved enough to secure the Claret Jug.

Oosthuizen, winner by seven strokes at this venue five years earlier, had looked the man to beat as he one-putted the last three holes of his final round and the first of the play-off in a nerveless display.

Leishman, meanwhile, could take great heart from his best finish in a major - just months on from being forced to contemplate retirement as his wife Audrey fell seriously ill and was placed in an induced coma. She is thankfully on the road to recovery.

As Johnson faltered prior to his closing birdie, Leishman - who shot the lowest round of the week when carding 64 on Saturday - briefly found himself two clear before dropping a shot on the 16th and signing for a 66.

There was still plenty of drama ahead, however, and Spieth threatened a stunning fightback when he followed birdies at nine and 10 - after his nightmare on eight - by holing a monster putt on 16 to tie the lead.

The 21-year-old bogeyed the next, however, and had to settle for a share of fourth alongside Jason Day, another to hold the lead overnight along with amateur Paul Dunne.

Day was in contention throughout, but 12 pars in a row - following birdies at the fifth and sixth - were not quite enough for a player who has now posted six top-four finishes in majors without winning.

Perennial Open challenger Adam Scott, who threw away the 2012 tournament at Lytham by bogeying the final four holes, again struggled badly down the closing stretch having been right in contention.

A series of excellent putts lifted Scott into a share of the lead through 10 holes, but he came back in 40 to finish 10 under - dropping five shots from the 14th.

Sergio Garcia, Justin Rose and Danny Willett all shot 70 to beat Scott by one, but Padraig Harrington fell by the wayside, a 75 leaving him eight off the pace.

Jordan Niebrugge claimed the Silver Medal as fellow amateur Dunne slipped back to six under with a 78.

Niebrugge's final-round 70 gave him a total of 277, the lowest by an amateur in The Open, while Oliver Schniederjans (-9) and Ashley Chesters (-9) also beat the previous record of 281 jointly held by Iain Pyman and Tiger Woods.