The 25-year-old American, who went into Sunday's final day as joint leader with the Masters champion on 11 under par, carded a 66 to finish on 15 under, two shots clear of the field at the Renaissance Club in North Berwick. 

McIlroy's hopes of heading for Royal Portrush with another title under his belt faded away as a round of 68 left him in a tie for second place with England's Marco Penge, who also shot 66, on 13 under. 

"Amazing. It's all hitting me. It's just so cool. I played really well this week. I knew today was going to be tough and I hung in there like a champ and finished it off in style," said Gotterup. 

"I felt pretty good, shockingly, on the first tee today, I felt comfortable. I knew I was playing well this week and I felt like I was ready for the challenge. That's why I practise and that's why I play, to play against the best. 

"It was a pleasure to be out there with Rory and obviously all the support that he gets is amazing, but it was nice to kind of ruin that a little bit." 

Nicolai Hojgaard, who tied with Fitzpatrick for fourth place, and Matti Schmid also claimed Open spots.

McIlroy, aiming to win the tournament for the second time in three years, led after back-to-back birdies on the 4th and 5th holes. But after a birdie on No. 8, he had pars across each of the last 10 holes.

Gotterup used four birdies on a six-hole stretch ending at No.12 to move to the top. He held a two-shot edge until his bogey on 15, where he hit his tee shot in the rough.

But on the next hole, Gotterup rolled in a 10-foot birdie for a two-shot advantage again.

The best round of the day belonged to England's Justin Rose, who shot 63 and moved to sixth place at 11 under, which was one shot better than Austria's Sepp Straka (67).

Australian veteran Adam Scott enjoyed an encouraging final round of 67 which left him tied for 17th at six under, while Elvis Smylie also went round in three under to finish a couple of shots behind the 44-year-old.

World No.1 Scottie Scheffler finished tied for eighth at nine under after his second 67 of the tournament.

Defending champion Robert MacIntyre of Scotland had a 71 for the second time this week and finished at two over, tied for 65th.