An emotional Oliver Wilson admitted he could be "drunk for a while" following his win in the Alfred Dunhill Links Championship, after starting the week ranked 792nd in the world.
Wilson, who finished runner-up nine times on the European Tour before losing his card, recorded a closing 70 at St Andrews to finish 17 under par, one shot ahead of world number one Rory McIlroy, Tommy Fleetwood and Richie Ramsay.
Belfast's Michael Hoey had a 73 to leave him on eight under.
Fleetwood, who was playing alongside Wilson, missed from 10 feet for birdie on the last to force a play-off, while Ramsay was two clear of the field after his eighth birdie of the day on the 15th, only to bogey the 16th and 17th in a closing 67.
McIlroy double bogeyed the first after misjudging his approach and seeing his ball spin back into the Swilcan Burn, and although he birdied the next four holes and made two more on the 10th and 12th, his chances ended when he putted into the Road Hole bunker on the 17th.
But the likeable Wilson's win was so popular amongst his fellow professionals that McIlroy summed up the mood by writing on his Twitter account: "Don't think I could've chosen a better person to finish 2nd to this week! Congrats @Oliver-Wilson so well deserved!"
Wilson is ranked a lowly 102nd on the Challenge Tour but claimed the first prize of almost £500,000 and a two-year exemption on the European Tour, moving from 252nd to 39th on the Race to Dubai.
"I don't have words for it," Wilson said. "It's been 10, 11 years coming, nine runners-up and I hadn't done a whole lot (wrong) to lose those but nothing has really gone my way.
"I know so many people had written me off and that hurt, but I just kept believing and a lot of people around me helped. I can't thank them all enough but they know who they are.
"I slept awful last night, I thought about a lot of things that this could do for me but to be honest I probably didn't genuinely believe, then I got on 17 when I holed that putt and started thinking what were the possibilities.
"The tournaments that I am now going to be able to get in... I don't have to go back to qualifying school and I can't tell you how pleased I am about that. I don't know all the implications yet but it will be fun to work out.
"I could be drunk for a while. It's been a long time coming. I've got a lot of champagne on hold from over the years. It will be a good party."
Wilson still needed to get up and down from 90 yards short of the 17th to save par and did a far better job than McIlroy managed from much closer to the green, the four-time Major winner suffering the embarrassment of putting into the dreaded Road Hole bunker.
"I didn't really leave myself much of a chance there," McIlroy admitted. "If you're going to miss it, you need to miss it right there and I didn't. It was tough.
"Where I feel like I cost myself the tournament was probably in the space of about 20 yards at the front of the green at the first and over at the Road Hole bunker. Not too far away from each other. They are the two things, the only mistakes that I made all day."
McIlroy was reluctant to blame fatigue for his mistakes, but admitted: "I'm not 100 per cent. My excitement level didn't get above about three at any point during the round. I'm ready for a break.
"(But) I love this golf course. I feel like I play well here every time I tee it up so I am looking forward to coming back here in July and defending the Open."