Clarcam made the most of a serious mistake from hot favourite Vautour to grab Grade One glory in the Racing Post Novice Chase at Leopardstown.
Vautour was a stunning winner of the Supreme Novices' Hurdle at last season's Cheltenham Festival and looked every inch a top-class chasing prospect when comfortably seeing off Clarcam on his debut over fences at Navan last month.
Clarcam had since opened his own chasing account at the same track, but it was no surprise to see Vautour sent off the 1-4 favourite to confirm his superiority.
Clarcam, an 8-1 shot for Gordon Elliott and Bryan Cooper, took the field along down the back straight, with Vautour shadowing him in the hands of Paul Townend.
The pivotal moment in the contest came five fences from home as Vautour made a shuddering error that left him with his nose on the turf before being picked up by Townend.
Cooper sensibly took the initiative, sensing an upset was on the cards, and Clarcam quickly opened up a break on the chasing pack.
He was clear rounding the home turn and winged the final fence to seal his wide-margin victory.
Vautour, unable to recover from his mishap, dead-heated for second with Ted Veale.
RaceBets cut Clarcam to 14-1 from 25-1 for the Arkle Trophy at Cheltenham in March.
Elliott said: "It's great for Bryan as this is the horse he broke his leg on at Cheltenham. I know Vautour made mistakes but my horse didn't just win a length or two - he destroyed them.
"We'll look at coming back here for the (Irish) Arkle and see what happens then."
Elliott went on to complete a double as 13-2 shot Space Cadet landed the bumper under Jamie Codd.
Vautour's trainer Willie Mullins suffered another reverse in the Knight Frank Juvenile Hurdle as his runaway Fairyhouse winner Kalkir (4-7 favourite) was put in his place by Des McDonogh's 33-1 shot Fiscal Focus.
Formerly trained by Jim Bolger and making his jumping debut, Fiscal Focus was good value for his two-length victory to leave McDonogh dreaming of a return to the Cheltenham Festival.
McDonogh, trainer of the great Monksfield, said: "I've not been to Cheltenham since 1987 and said I wouldn't go back unless I had a runner. I'll have to sit down and talk with Jim (Bolger) here tomorrow before we decide what to do.
"He jumped great for his first run over hurdles and has beaten one of the favourites for the Triumph Hurdle. I'm still in a bit of shock!"
Despite the disappointing efforts of Vautour and Kalkir, it was not all bad news for the Mullins team.
As well as seeing Faugheen enhance his Champion Hurdle claims with a brilliant victory at Kempton, Alvisio Ville burst onto the scene with a stunning Irish debut in the Bewleys Hotels Maiden Hurdle.
Townend barely had to move a muscle as the 1-2 favourite eased to a five-and-a-half-length success.
The trainer's son, Patrick, said: "He showed there what he's showing at home. He's 17.2 hands and has a huge stride.
"As they were going faster he jumped better and we think he's very, very good."
Jessica Harrington's mare Rock On The Moor (12-1) beat the boys in the Thornton's Recycling Maiden Hurdle under Robbie Power.
Harrington said: "The ground at Navan was sticky (when third) which affected her and I felt she was back to where I thought she'd win.
"She was jumping beautifully at home and the plan now is to target a mares' Listed race at Fairyhouse in mid-January.
"That's made my Christmas!"
Dermot McLoughlin's Westerners Son (16-1) got up on the line to deny the front-running Follow The Sign in a thrilling Cardinal Capital Handicap Hurdle.
McLoughlin said: "I was hopeful beforehand but thought he'd need the run badly. The other horse was in front a long time.
"He's come back from injury and hopefully he's OK in the morning."
Forty Foot Tom (10-1) turned in a bold-jumping display in the Racing Post All You Need For Irish Racing Handicap Chase.
Winning trainer Danny Miley said: "He really wants further and better ground but he got away with the trip on that ground.
"Once you know this horse's ways he's a grand horse to have."
