Tiger Roll became the first horse to win back-to-back Grand Nationals since the legendary Red Rum after storming to victory at Aintree racecourse.
The 4-1 favourite never looked daunted, despite being the smallest horse in the 172nd edition of the race, and cruised home in the long run-in to win by three lengths from 66-1 shot Magic of Light in second.
Rathvinden (8-1) finished third with Walk in the Mill (25-1) in fourth. Anibale Fly was fifth and former winner One For Arthur finished sixth.
Out of a field of 40, 19 horses finished the course, but one - Up For Review - died from severe injuries after falling at the first fence, becoming the race's first fatality since 2012.
"It's incredible. I thought he had no chance -- what a horse!"
Red Rum - recognised as the greatest horse in British racing history - won successive Grand Nationals in 1973 and 1974 before adding a third title in 1977 to cement his legacy.
Now Tiger Roll has emulated the first part of that stunning trio, reaching a new status as the first horse in 45 years to complete back-to-back victories, and at the age of nine he could yet have more opportunities to move level with the legendary gelding.
The horse - trained by Gordon Elliott and owned by Ryanair chairman Michael O'Leary - was guided seamlessly through the nearly 7-kilometer long course by jockey Davy Russell, who timed his final strike for victory perfectly.
A complicated chase had seen the hot pre-race favourite mainly kept out of trouble by Russell in the packed field in Liverpool before a mistake four fences from home looked likely to prove costly.
But the pair's recovery was magnificent and they chased down Ruby Walsh's mount Rathvinden over the next two fences to make it a two-horse race with Magic of Light going into the final jump.
Off that final fence Tiger Roll powered clear in the sunshine, leaving tired rivals in his wake to give a delighted Russell a second-straight victory.
"He's just an unbelievable horse," Russell, 39, said of his mount. "I can't believe it. At my age now to win two Grand Nationals -- wow!"
Trainer Elliott could hardly contain his joy in the winners' enclosure, jumping around and hugging the horse that was bought for £10,000 ($13,000) to "sell on" because he was thought to be on the slow side.
"What a horse, what a horse," Elliott said. "We worked very hard for this the whole time and I have a brilliant team behind me. Davy Russell's mum died last year and this was for her."
Elliott also trained 2007 winner Silver Birch.
O'Leary added: "It's incredible. I thought he had no chance. What a horse. He keeps improving I just don't understand him. I'm so thrilled."
Information from Reuters contributed to this report.