Wells' shot at history has been put to rest before the halfway mark of the Grand National Steeplechase at Ballarat with jockey Richard Cully falling from the favourite.

Attempting a fourth win in the National, Wells put in a faulty jump at the fifth fence of Sunday's 4500m-race and parted company with Cully.

Wells, who shares the the National record with Bashboy, had won the race in 2014 at Sandown, adding Ballarat victories in 2016 and 2017.

"I just stood off too far and landed in the middle of it and unfortunately I couldn't stay on," Cully said.

While the race didn't go to plan for Wells, another veteran Sea King landed a last-stride victory to give trainer Patrick Payne his first win and jockey Steve Pateman his fourth.

Sunday was Sea King's fourth shot at the National having finished third in 2014, fourth in 2016 before falling when in contention last year.

Payne deflected the credit for Sea King's victory to New Zealand trainer Kevin Myers.

"I can't stick my chest out," Payne said.

"They sent him over fit and well and all I had to do was keep him breathing."

Payne said Sea King had become a stable favourite in the five years he had been coming to Australia.

He added he was a quirky individual.

"He lays in and lays out and he's almost got barred in New Zealand a couple of times," Payne said.

"For a degree of difficulty he's an unbelievable ride but he (Pateman) makes it look relatively easy."

Pateman said he felt for connections of Wells in their chase for history.

"It was a really thrilling win and I'm sorry what happened with Wells," Pateman said.

"But that could have happened to any of us.

"That's the game."

Pateman missed a chunk of the 2017 jumps season through injury and said Payne had a plan leading into this year's race.

"I'm so privileged to ride for him," Pateman said.

"People kept thinking I was going to retire but there was no plan to retire which I think was a flow-on effect from breaking my leg last year.

"Oakbank and Warrnambool were good but June and July were terrible.

"That's why I'm a bit emotional."

Jockey Will Gordon who fell from John Monash was taken to Ballarat Hospital for x-rays on a suspected fractured collarbone.