Jadanli claimed a dramatic race for the Powers Gold Cup at Fairyhouse after Zaarito fell at the third-last fence in the Grade One contest.
There was little to choose between the two at that obstacle, but the luckless Zaarito landed too steep and came down, leaving the race at Jadanli's mercy.
The 25-1 shot jumped the remaining fences but was out on his feet on the testing ground in the closing stages. However, it was chaos behind him as Roberto Goldback fell at the final jump, Shakervilz was hampered and unseated Ruby Walsh, while weary long-time leader Let Yourself Go refused.
Jadanli, meanwhile, kept going for Andrew Lynch to win by 23 lengths and follow up the jockey and trainer Paul Gilligan's win with Berties Dream at Cheltenham.
Deal Done plugged on for second while Shakervilz was remounted to claim third prize. They were the only finishers, with Zaarito's fall being his fourth in seven starts over fences.
'He ran well at Navan the last day. He's a family horse, he injured his tendon and missed two years so it's great to get him back,' said County Galway handler Gilligan.
'We thought about the Irish National but as he was a novice we left it. That'll be the long-term plan for next. He will go for the three-mile novice chase at Punchestown next.'
Davy Russell came to grief at the second fence on Jagoes Mill in the feature race but he took the riding honours with a glorious 99-1 treble on Luska Lad, For Bill and Quito De La Roque.
Luska Lad put up a tremendously game performance to snatch an unlikely victory in the Rathbarry & Glenview Studs Novice Hurdle.
Blackstairmountain appeared to have his measure when going on just before the final flight, but Luska Lad found extra on the run-in.
Russell had attempted to make all on the 11-10 favourite, but was stalked by Walsh on Blackstairmountain who looked to be going the better as they turned for home and had a good length advantage after the last.
However, Willie Mullins' charge could not quicken on the tiring ground and Luska Lad, who was switched from the rail after the last, rallied bravely to get back up close home and win by three-quarters of a length.
'We will now go for the Evening Herald Champion Novice Hurdle at Punchestown,' said winning trainer John 'Shark' Hanlon.
'He stays and is very tough with the way he battled back there.
"I think he's an even better horse on better ground. We'll go to Punchestown but I also have it in my mind to take him to France.'
Russell completed a quick double with a smooth victory on For Bill (100-30) in the Irish Stallion Farms EBF Mares Novice Hurdle.
And again it was Walsh in second place on Morning Supreme, who had shared the lead for most of the race with Premier Victory.
Russell brought For Bill wide to make her bid in search of better ground. Taking it up before the last, Michael Winter's seven-year-old forged clear to score by eight lengths.
Delighted winning owner Donal Sheahan said: 'That's as good as Kerry winning the All-Ireland.
'She'll be a good mare to go chasing but she'll have a break now, just like myself!"
Russell gave trainer Colm Murphy some compensation for Zaarito's fall when completing his trio on Quito De La Roque (10-1) in the INH Stallion Owners EBF Novice Handicap Hurdle Series Final.
The jockey brought his mount with a well-timed run to join issue with Ad Idem at the final flight and go on to win by a length and a quarter.
'He did that very well. He got his conditions today, three miles on soft ground. The softer the better for him,' said Murphy.
'The ground will dictate his plans really, if it stays soft we'll keep him on the go or if it dries up we'll wait until the other side of the summer.'
Murphy added of Zaarito: 'He's fine after his fall, he's a frustrating sort but hopefully things will go right for him.'