Wells gave another faultless display of jumping to win Sunday's $120,000 Crisp Steeplechase (3900m) at Sandown.
Richard Cully had to settle Wells in last place after a slow start in the small field before beginning to creep closer after halfway.
Over The Yardarm had a clear advantage around the home turn as Wells gave chase, jumping the last fence in second place.
Wells ($1.65 fav) gradually asserted his superiority on the run inand prevailed over a gallant Over The Yardarm ($14) by a half head with King Of The Forest ($17) a further seven lengths away in third.
Wells won the Grand National Steeplechase last year and came into the race having won the Mosstrooper Steeplechase last time out at Bendigo.
Trainer Kath Durden said she had her doubts approaching the last fence.
"I just thought he was going to have to lift and I just hoped his staying prowess would kick in," Durden said.
"I was worried about him on a heavy(9) track and he was just so brave. I've always said his best is on a soft track but he managed to handle this today.
"He's just a super horse."
The Grand National Steeplechase in two weeks time is next for Wells and rider Richard Cully said the son of Galileo found plenty for him.
"He dug deep, I was always confident he'd find the line," Cully said. "He's tough and he's done it before.
"Giving the weight away, it was a huge effort. I didn't want to rush him to get there up the hill, he's just an unreal horse.
"He jumps so well and is so tough."
