Sizing John could find himself in the Ryanair Chase at Cheltenham in March after coming home best to claim top honours in the Ladbrokes Ireland Kinloch Brae Chase at Thurles.
Recently-retired Cheltenham Gold Cup hero Don Cossack had claimed the last two renewals of the Grade Three contest and his owners, Gigginstown House Stud, were responsible for the 11-10 favourite Sub Lieutenant, trained by Henry de Bromhead.
Sizing John, a former inmate of De Bromhead's but now with Jessica Harrington, was a 3-1 shot to get back on the winning trail, having been placed behind the brilliant Douvan for the seventh time at Leopardstown over the festive period.
Smashing took the six-strong field along for much of the two-and-a-half-mile journey, with Sub Lieutenant and Sizing John his closest pursuers.
Sub Lieutenant hit the front before the home turn and looked to have matters in hand under David Mullins, but Sizing John responded to Robbie Power's urgings and quickened up well as the pair went by the omitted final fence to get up and score by two and a half lengths.
Black Hercules boxed on for third after being under pressure a long way from home.
Harrington said: "He was very relaxed all the way through the race, and Robert said when he popped the fence after turning into the straight that he was always going to pick up.
"I'm delighted with him stepping up to two and a half miles, and he got the trip very well.
"I'll have to speak with Alan and Ann (Potts, owners) to see where we go next with him.
"He has an entry in the Irish Gold Cup or he could go to the Red Mills at Gowran, and he's in every race at Cheltenham.
"You would imagine he is likely to go for the Ryanair but we will have to wait and see."
Power said: "When I rode him in Leopardstown over two miles - I know Douvan was in there - I was flat to the boards the whole way.
"This time he was so laid-back the whole way. I knew I had plenty left and he has that bit of speed as well.
"I knew when I gave him a squeeze he'd pick up and he galloped all the way to the line.He's so lazy in a race, I think he'd get any trip.
"The Ryanair Chase looks made for him this year, I'd imagine."
The final fence was omitted as jockey Phillip Enright was attended to by medics after suffering a heavy fall from Letter Of Credit on the first circuit. He got to his feet, but was later taken to hospital for X-rays on his jaw.
Harrington looked set to complete a double for much of the Champs Elysees Coolmore National Hunt Sires E.B.F. Mares Novice Chase, with Keppols Queen leading her rivals a merry dance.
However, the prolific Westerner Lady (4-6 favourite) responded to Ruby Walsh's urgings to make a race of it and had just drawn alongside when Keppols Queen crashed out at the final fence.
Westerner Lady was left in the clear and passed the post two and a half lengths clear to secure her 10th career victory and her first at Grade Two level.
Her stable companion Daisy's Gift completed a one-two for Willie Mullins.
"She has been a fantastic servant to us all year and is doing way more than we envisaged. We were supposed to give her a break, but I'm not going to until she gets beat," said the champion trainer.
"We will keep her to mares' races. She tends to jump a bit out to the left but Ruby was happy enough, and she probably prefers being out on her own a bit anyway.
"I will keep her to this job (fences), and I don't think we will enter her for Cheltenham."