The Arkle Chase winner was sent off the uneasy 4-9 favourite to preserve his unbeaten record over fences but he made a bad mistake at the third fence and generally lacked fluency.
The writing was on the wall for him, and hius many supporters, when he all but fell at the last and unseated Ruby Walsh.
"Footpad has an overreach in front," trainer Willie Mullins said. "He might have got it when he made the mistake (at the third fence). He's quite sore and to me that's enough to stop a fluent jumper from jumping.
"He was very sore when he jogged in the stable yard after cooling down, and hopefully it's just an over-reach."
By contrast, British raider Saint Calvados hardly hit a twig hands of Gavin Sheehan, putting Footpad under pressure from an early stage in the Grade Three contest.
Sheehan lifted the tempo turning for home and Harry Whittington's flamboyant jumper held a three-length lead at the last, where Footpad slithered badly, giving Walsh little chance of keeping the partnership intact.
Saint Calvados (5-2) was left clear and coasted home by four and a half lengths, with Tycoon Prince claiming second place.
The winner was cut to 5-1 from 8-1 for the Betfair Tingle Creek Chase at Sandown on December 8 with the sponsors.
Whittington said: "He'll go for the Tingle Creek next and I'm looking forward to him going over the Railway fences there. He was just a bit rusty over the first couple, but it was a good performance.
"I'm delighted for Andrew and Kate Brooks (owners) and for the horse. You can just draw a line through the Arkle now, and he's probably silenced the doubters. He's come back and done it well.
"He's a proper two-miler, and Gavin felt he was just hacking round. He's only going to get better with age, as he's still a big, raw horse and only five. It's very exciting."
Looking further ahead, Whittington said: "He's in the King George. I was trying to convince Andrew not to enter him so we didn't get tempted, but Andrew said you can blame it on the owner. But he's a two-miler with that raw pace.
"After the Tingle Creek he may have a break and come out somewhere in February as a prep for Cheltenham, if all goes to plan, but it's up to Andrew.
"He's a much stronger horse now and his work has improved significantly at home. He's more the finished article and he'll get even stronger next year. It's super, super exciting!"
There was more disappointment for Walsh and Mullins when Espoir D'Allen took advantage of the fall of Saldier at the final flight to land Grade Three honours in the Fishery Lane Hurdle.
The Walsh-ridden Saldier had gone on from long-time leader Mastermind at the second-last, but was being pressed by Espoir D'Allen when he came down.
Espoir D'Allen (3-1) strode away on the run-in for trainer Gavin Cromwell, to score by 11 lengths from Mr Adjudicator.
Cromwell said: "You would love to do it on merit and I don't know if he'd have won. It was all up in the air. He was fit and well, but I really didn't know coming here was he good enough. I'm delighted with that.
"He's in the Hatton's Grace and stays well so I wouldn't rule it out. He hasn't been seen since February, and it was a case of getting this out of the way and seeing where we were. It's a fair yardstick in fairness."
It was double on the card for jockey Mark Walsh and owner JP McManus following the victory of the highly-regarded Rhinestone in the opening hurdle race.