Willie Mullins' lightly-raced eight-year-old looked a potential superstar when beating Defi Du Seuil at Punchestown last spring.
He did not reappear until Christmas, when he was surprisingly beaten by Henry de Bromhead's A Plus Tard and a rematch was on the cards.
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However, A Plus Tard was a late absentee as De Bromhead felt the ground was too quick to run his charge and when Mullins' Cilaos Emery departed at the first fence, Chacun Pour Soi's task was further eased.
His main danger was stable companion Min, winner of the race for the past two seasons, but Paul Townend's mount breezed past him at the second last before keeping up to his work for a three-and-three-quarter-length win as the 6-5 favourite.
Townend said: "There was no hiding place and we went a proper gallop. He jumped like a buck every step of the way and put himself right at the last.
"I was hoping for something like that and thankfully he produced it. Min has run a great race as well and is a good yardstick.
"I felt this horse was the two-miler and Min wanted two and a half coming into the race today. Min set the standard and I was hoping this lad could improve past him.
Townend gives his reaction to Nick Luck
"He's brave and jumps great. Whether he's good enough to win a Champion Chase, I don't know, but he'll be there to have a go.
"It's safe ground and they have done as good a job as they can with it. This wind is drying it out."
Mullins said: "He was electric jumping. Jumping those fences down the back, he was so slick and so fast. He was getting a length or a length and a half at every fence without any effort
"Paul said he just arrived up beside Min at the third last and he didn't want to hang around, so just kept going.
"He idled, which is a good sign I think. It just shows how much he improved since Christmas.
"All that worked out and he was here today in top form. It's a nice prize to win.
Mullins was taken by Chacu Pour Soi's electric jumping
"Min was the horse to beat in the race. It was a tough choice for Paul to make - looking at the race afterwards, you'd say maybe it wasn't.
"To me, Min was the one to beat, but he didn't get things his own way with Ornua up there. If Ornua hadn't been there, it would have been a much closer contest I think.
"Chacun Pour Soi looks the horse of the future and I think that's why Paul made the decision - he thought this was the horse that was coming up.
"The first day I brought him up here for Cheltenham trials day last year, I let him go around with a few of ours.
"I said to Danny (Mullins), who rode him then, to follow around, but after two fences he was in front and led all the Cheltenham horses.
"It was absolutely eye-opening. Once every two or three years, you get a horse coming up the gallop that shows you something that he shouldn't be able to do and that's what he did that day.
"First day here over fences, he had handicap chasers and Grade One horses behind him and he was a novice. I said 'wow we could have something here' and he's turned out that way.
"Min might look more a Ryanair horse now. We'll have a look and see what's in both races.
"He's still a very competitive two-miler. We might elect to ride him a little different as we got our tactics completely wrong last year.
"There is no shame in finishing second or third if Chacun Pour Soi can do that and it's nice to have a reserve like Min in the line-up too.
"I'm not going to just jump straight over to the Ryanair for Min as I want to see what we have going for both races."
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