Shishkin charged home to collar Energumene as the epic Ascot duel lived up to the hype.
The SBK Clarence House Chase, which drew the crowds to the royal venue, was full of drama from the outset.
Energumene set out to make the running and jumped the obstacles slickly under Paul Townend.
Shishkin on the other hand made a couple of mistakes and stumbled at the sixth fence as the Irish raider led the field.
Nicky Henderson's charge was on the outside as Energumene looked to have his measure at the final fence.
But in his customary fashion, Shishkin stayed on powerfully to race ahead by a length.
He received a huge reception from fans on the way in, as punters hailed the performances from both horses on social media.
"I don't get excited very often but going down that hill flat out on these two, myself and Paul (Townend), the thrill and exhilaration of doing that is hard to buy," said winning jockey Nico de Boinville.
"What a fantastic horse, he had to be so gutsy and the handicapper was right, rating them 171 and 172.
"We were going so fast he was coming alive under me too much and I had to settle him down again. He was losing ground going out to his left but great champions find a way of winning and he's just that."
Henderson added: "It was built-up and it produced. Two great horses and it was rather fun. Good old Seven Barrows, a race like that goes back to the Grundy v Bustino days.
"Shishkin only lives around four boxes away from Grundy did. There was no point hiding today, Energumene was going to set a good gallop and we had to stay in touch with him. There were moments it looked as if we weren't go as well but it proves he stays very well.
"God willing they both come home safe and sound and there is going to be a re-match. I always said I hoped it was a good race today because it won't ruin the Champion Chase. They'll be back to fight it again together. Willie and I have jobs to do to get the back from a hard race but there's plenty of time."
Shishkin is 8-11 for the Queen Mother Champion Chase at Cheltenham in March, while Energumene is a top price of 3-1.
The latter's trainer Willie Mullins said: "I was shaking on the stands after the horses passed the winning post. It was a terrific race, two good jockeys, two good horses and played down to the wire.
He added: "It could be very difficult (to reverse the form). We jumped very well there, we had our own way in front and Nicky's horse made one bad mistake and maybe another blunder and he has that up his sleeve."
