Open 2015: Amateur Paul Dunne shares lead ahead of Monday’s final round

Jordan Spieth's calendar grand slam bid remained on track in the 144th Open Championship, though the 21-year-old American was forced to settle for fourth place going into Monday’s delayed final round at St Andrews.

It was instead 22-year-old Irish amateur Paul Dunne who stunned the golfing world with a sensational round of 66, finishing tied at the top of the leaderboard on 12 under par, along with 2010 winner Louis Oosthuizen and Australia’s Jason Day.

Masters and US Open champion Spieth, who also carded a third-round 66 with seven birdies and one bogey, faced a large number of challengers, with the top 14 players separated by just three strokes.

After a weather-affected tournament so far, the skies finally cleared on Sunday afternoon to allow the players produce their best golf on the legendary links, with the lead changing hands with amazing regularity.

England’s Danny Willett was in the final group and had birdied the fifth, ninth and tenth to take the outright lead after ten holes, but Dunne moved alongside him with a birdie on the 15th, before Willett drove out of bounds on the 14th and dropped to nine under.

Two-time Open champion Padraig Harrington was a shot further back from Speith in fifth place after a superb 65.

Eight other players were tied for sixth with Willett on nine under, including another amateur in American Jordan Niebrugge, along with Justin Rose, Sergio Garcia and Adam Scott.

Dunne is the first amateur since the legendary Bobby Jones to lead the Open after 54 holes, the American going on to lift the Claret Jug at St Andrews in 1927.

Three years later, Jones became the last amateur winner of the Open to date at Royal Liverpool and went on to complete the "Impregnable Quadrilateral" of Amateur Championship, Open Championship, US Open and US Amateur titles.