Apple's Jade had to dig deep to collar Supasundae close home and land the Squared Financial Christmas Hurdle at Leopardstown.
But the Grade One race was marred by the fall of Stayers' Hurdle hero Nichols Canyon, who came down at the fifth flight in front of the stands and was attended to as the obstacle was omitted on the final circuit.
He sadly had to be put down.
An eight-time Grade One winner, Nichols Canyon is the only horse to beat the mighty Faugheen.
The seven-year-old, who carried the colours of Andrea and Graham Wylie, lifted the Stayers' Hurdle at the Cheltenham Festival in March for what proved to be his final success at the top level.
But arguably his greatest triumph was when lowering the colours of his stablemate Faugheen in the 2015 Morgiana Hurdle at Punchestown.
Nichols Canyon won 12 of his 20 career starts and amassed £707,000 in prize money.
The two principals cut out the running between them over the three miles and it looked for a long way as though Supasundae would come out on top, until Apple's Jade (4-6 favourite) - who was trying the trip for the first time - pulled out more on the long run to the line.
Davy Russell, who was replacing the injured Jack Kennedy, got extra out of the Gordon Elliott-trained mare to snatch the verdict by half a length for owners Gigginstown House Stud. Bapaume was third.
Russell said: "She's something else. I've only ridden her at home and it's a pleasure to ride her, even at home.
"Lisa O'Neill does all the work on her, but really Jack (Kennedy) is the man that has probably made her and unfortunately he got a couple of horrid falls during the week.
"All credit has to go to Jack, Lisa and the team at home, really. I knew when I got stuck into her she'd find loads - Supasundae ran well in Fairyhouse and I knew he'd stay, but to be fair, Apple's Jade is all heart.
"It's amazing what a good filly can do."
Apple's Jade wins the Grade 1 Christmas Hurdle at Leopardstown in battling fashion but the race is marred by a fatal injury to Nichols Canyon pic.twitter.com/W5l1BK01WU
— RTÉ Racing (@RTEracing) December 28, 2017
RaceBets cut Apple's Jade to even-money favourite from 6-4 for the OLBG Mares' Hurdle at Cheltenham in March.
Elliott said: "Davy said if he rode her again he would have got her into a battle earlier, but in fairness she was in front where it mattered. She just loves a battle and won by half a length at the end.
"Davy gave her a great ride, but she's Jack's mare and Jack will be riding her the next day. He got a couple of falls and he was very sore this morning, so he couldn't ride, but she's Jack's ride and he'll be back on her the next day.
"She'll be against the girls next time in Cheltenham, the mares' race is the plan. She's just five years old and has now won seven Grade Ones.
"It was very unfortunate what happened to Nichols Canyon."
Hardback put up a gutsy display to stave off Low Sun in a thrilling finish to the Irish Daily Star Christmas Novice Handicap Hurdle.
There was nothing between the pair on the dash to the line from the final flight, but 3lb claimer Shane Shortall forced the Joseph O'Brien-trained six-year-old past the post as a narrow winner.
The 16-1 shot was completing a quick double for owners Gigginstown House Stud following the success of Apple's Jade.
"It all worked out well. We tried a different tactic with him today and dropped him in and switched him off, as he was doing a bit too much in his previous races and not getting home," said Shortall.
"Things worked out really well that way and he came home really well. He missed the last, but stuck his head out and tried hard under top weight. It was a good performance."
