The King George VI Chase and the Cheltenham Gold Cup could be among Shishkin's targets next season after the top-class chaser kicked in the turbo to secure the Alder Hey Aintree Bowl.
Nicky Henderson's charge earned superstar status by winning his first 10 completed starts over obstacles, a run which included successive victories at the Cheltenham Festival and three Grade Ones.
The wheels came off in last season's Champion Chase, with Henderson putting his abject performance on desperate ground down to a rare bone condition, while a fairly uninspiring start to the current campaign in the Tingle Creek at Sandown suggested his best days may be behind him.
Not for the first time, however, Henderson weaved his magic, getting Shishkin back to something like his best when stepped up in trip for February's Ascot Chase, after which he did remarkably well to finish second in last month's Ryanair after a performance lacking much zest.
The Seven Barrows handler felt the time had come for his former star two-miler over three miles and he was the 7-4 favourite to successfully graduate to the staying trip on Merseyside.
Once again it was not entirely plain sailing, with Nico de Boinville having to get lower in the saddle on a couple of occasions while Ahoy Senor attempted to make all under Brian Hughes.
The latter looked likely to prevail after drawing clear between the final two fences, but as has been the case on a few occasions over the years, Shishkin saved his best for late in the day, thrusting home on the run-in to get up and beat Ahoy Senor by a length and a half.
Henderson said: "He's a very good horse and that was a very good race, fair play to Ahoy Senor, he was going well in the Gold Cup when he came down. It was a genuine Grade One race. We were almost here to find out who was second best - without Bravemansgame we haven't really solved that.
"He was so much better today than at Cheltenham. He does finish very well, he's tough and he stays but he is getting quite lazy in his races.
"He's won that by staying - his first race over three miles - so the trainer has got it wrong for the last two years, we know that!
"We admitted that after the Tingle Creek, he won a Grade One over two-mile-five at Ascot, we thought we were right staying at that trip in the Ryanair but to be honest he wouldn't have won over any trip.
"There were a few issues, he was very sore all over and we've had lots of people working on him. We took the tongue tie off as he didn't like that. We've got to tweak things and that's our job. I think it's body not mind."
Henderson will now stick at three miles with Shishkin, with the King George VI Chase at Kempton an "obvious" target next term.
He added: "Three miles is where we'll stay, we won't be coming back. I know the Gold Cup is not much further than this but it is a different track. The obvious place is the King George, then take it from there. Whether you go Betfair and then King George, you are fairly limited in your options but the King George is the obvious target. He won't go to Punchestown now.
"He used to be very straightforward but like everybody, he gets a bit creaky. We had the four weeks and it's all worked.
"When you are racing over three miles you want them racing lazily, you don't want them to be keen when you up them in trip. You'd rather see him wake up a little bit more, we'll see, I might have a few more tricks yet."
Lucinda Russell was more than satisfied with Ahoy Senor's effort in defeat.
She said: "I'm exceedingly proud of him and let's face it, Shishkin is a fabulous horse who keeps galloping.
"It must have been hard for Brian (Hughes) who had never ridden him before, but he thought he had them at the last.
"I think he got tired eight strides before the last, he made that mistake and he was slightly on the back foot."
A Plus Tard was the only other finisher in the five-runner heat, with Conflated and Ga Law both pulled up.