Danny Willett won his first green jacket and first major of his golf career Sunday, taking advantage of an opening after Jordan Spieth squandered the 12th hole.

Spieth appeared to be a lock to win his second consecutive Masters, leading after day 1 and into the back 9 on Sunday.

Leading by 5 strokes when he made the turn, Spieth quadruple-bogeyed the 12th, hitting two balls into Rae's Creek. His quadruple-bogey followed back to back bogeys. In only 3 holes, Spieth's 5 stroke lead turned into a 3 stroke deficit, one he couldn't recover from.

"It was a really tough 30 minutes for me that hopefully I never experience again," Spieth noted.

Willett kept a steady hand, playing bogey-free golf in the final round, seizing the opportunity.

"You dream about these kind of days and things like that, but for them to happen, it's still mind-boggling," Willett said in his green jacket.

Willett received his green jacket from Spieth, last year's winner, ending an unlikely and unexpected final day at The Masters.