Former champion Phil Mickelson’s charge up the leaderboard came to a dramatic end in the delayed final round of the Open at St Andrews on Monday.

Mickelson was six under for the day and just two off the lead at 10 under overall when he hooked his drive on the 17th out of bounds and into the Old Course Hotel.

The left-hander’s ball bounced off a conservatory roof and came to rest on the balcony of one of the hotel rooms, leading to a triple-bogey seven.

Mickelson, who also drove into the Swilcan Burn on the first hole in the third round, then saw his approach to the 18th spin back off the green into the Valley of Sin, from where his birdie putt hit the hole and lipped out.

The resulting par meant the 45-year-old had to settle for a closing 69 to finish seven under, five behind the leading trio of 2010 champion Louis Oosthuizen, Australia's Jason Day and Irish amateur Paul Dunne.

Dunne, 22, is the first amateur since 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.

American amateur Oliver Schniederjans was left to rue a double bogey on the 17th and while he took a shot back on his closing hole he had to settle for a final round 67, which leaves him at nine under par and just out contention.

Jordan Niebrugge, another American amateur, began his final round on nine under while English amateur Ashley Chesters was enjoying a fine day and breathing heavily down the back of the leaders - he was five under through 11 holes and just a shot off the top.

With an amateur winner a real possibility the R&A have announced the prize money will be split between the rest of the field who made the cut rather than going to the second placed player.