Amateur Paul Dunne says there is no reason why he cannot clinch a shock victory at The Open after surging into a three-way share of the lead on Sunday.

Irishman Dunne is ranked 80th in the official amateur rankings, but the 22-year-old is on the cusp of glory having shot a superb six-under-par 66 in his third round to join Jason Day and playing partner Louis Oosthuizen atop the leaderboard.

Dunne would end an 85-year wait for a non-professional winner at The Open, with the great Bobby Jones the last man to do so in 1930.

There is plenty of star quality at the top of the leaderboard, with Jordan Spieth - looking to complete the third leg of a calendar Grand Slam - just one stroke back, and two-time Open winner Padraig Harrington two shots off.

But Dunne is confident of upsetting the odds at St Andrews, and when asked if he could win the Claret Jug answered: "I don't see why not.

"I'm well capable of shooting the scores that I need to win if everyone else doesn't play their best. Whether it happens or not, I can't really control.

"I can just go out and try to play my game and see where it leaves me at the end of the day. Hopefully I play great again and post a good number."

But Dunne, whose score was the lowest by an amateur in Opens at St Andrews, is not getting ahead of himself.

"I think it'll be the same as the last three days, just look at the weather, see what the weather is going to throw at us and then put a number in my head that I think I need to shoot," he added.

"I'm not really going to think about winning or where I'm going to finish until the last few holes."

Dunne also spoke of his admiration for compatriot Harrington, who he says was one of the biggest influences on his career.

"I've always looked up to Padraig. He's been such a great ambassador for Irish golf. He carries himself so well and practises hard," Dunne said.

"He's been probably the most influential person in Irish golf definitely in modern history anyway. I remember watching him win The Open at Carnoustie in 2007 and 2008 at Birkdale."