Germany has celebrated its first Melbourne Cup triumph but Japan's challenge ended in heartbreak.

As the German-trained Protectionist romped away to a four-length victory a stricken Admire Rakti, the pre-race favourite, trailed in a long last.

Minutes later the seven-year-old from Japan collapsed and died in his stall.

The drama continued when seventh-placed Araldo was spooked on the way back to his barn and kicked at a fence breaking the pastern bone in its hind leg. Araldo was eventually put down by vets.

The trainer of Tuesday's Cup winner, Andreas Wohler, expressed his sympathy for Admire Rakti's team as he savoured Protectionist's win.

"I feel sorry for them. It is always sad," Wohler said.

Protectionist, who will remain in Australia, was the $8 third favourite for the gruelling 3200m race and was further back in the field than planned.

Admire Rakti ($5.50) tracked English mare My Ambivalent through the first two thirds of the race but both were spent before the turn.

Ryan Moore, who won the Cox Plate on Irish horse Adelaide, steered Protectionist between the gaps and once in clear air, the horse streeted away.

It was the biggest winning margin in nearly two decades since Doriemus also scored by four lengths in 1995.

Chasing Protectionist home was the gallant English visitor Red Cadeaux ($21), now a three-time runner-up.

Upholding colonial pride, Who Shot Thebarman ($21), a former New Zealander now trained in Sydney, finished another half-length third.

With Protectionist's owners Australian Bloodstock planning to keep him in the southern hemisphere, Wohler was philosophical about losing the horse he identified as a star very early on.

"I always thought he was something special but he stumbled over a deer when he was a young horse and that put him back," Wohler said.

"That is why he has only had a few starts. I knew he was the best horse in the race and I knew this was his last start for me.

"That was part of the deal. I'll just have to find new ones.

"This race is high up among the world's great races and I'd like to come back."

Who Shot Thebarman gave leading trainer Chris Waller his best Cup finish and his Kiwi owners were already planning for next year.

"Fourth prize money ($450,000) is pretty good," Humphrey O'Leary said.

"We'd like to come back next year."

Waller said he thought the horse was still maturing even as a six-year-old.

"He is a horse that likes 3200 metres but now we just have to try to get some speed in his legs to give that little bit extra."

Behind the placegetters, Lexus Stakes winner Signoff ($8) loomed up turning for home and held on for a solid fourth with Godolphin's Willing Foe ($31) fifth.

Precedence ($81) produced his best Cup finish in four tries for master trainer Bart Cummings and his grandson James with his eye-catching sixth.

Araldo's trainer Mike Moroney said the horse was spooked by a big flag after the Cup and ran away from it.

"It was a freak accident. They run the Melbourne Cup for 154 years and nothing like that has happened," he said.

There were a few hard-luck stories from the jockeys with Kerrin McEvoy on the $7 second favourite Lucia Valentina saying she failed to stay the distance.

Her trainer Kris Lees, however, still had plenty to smile about as Protectionist will join his stable from Wednesday.

The only truly Australian horse in the race, Fawkner, finished 10th under Nick Hall.

Bred by his owner Lloyd Williams, the 2013 Caulfield Cup winner was a spent force 800 metres from home.

"He was too close and struggled at the half-mile," Hall said.

Some of the others also struggled with 73 lengths between Protectionist and last-placed Admire Rakti.