Nicky Henderson saddled Buveur D'Air to become the first horse to win back-to-back Champion Hurdles since Hardy Eustace in 2005 - but it was a mighty close-run thing.
There was a treble for Mullins' compatriot Gordon Elliott, with Jack Kennedy delivering two of those wins on board Samco and Veneer of Charm in the Novices' Hurdle and Juvenile Handicap Hurdle respectively.
In a titanic struggle, the 4/6 favourite Buveur D'Air outstayed the fearless Melon (7/1) to win by a neck, giving the first of the week's big features to champion trainer Henderson and jockey Barry Geraghty, with outsider Mick Jazz (25/1) in third.
The Willie Mullins-trained Next Destination (4/1) stayed on strongly to finish a further five lengths behind in third.
It may have been Buveur D'Air's second consecutive Unibet Champion Hurdle triumph, but it was Barry Geraghty's first aboard the Nicky Henderson-trained seven-year-old. They've gone a gallop there. I imagine jockey Paul Townend will be delighted to be on top again and I wouldn't be at all surprised to see them come home in front of the big two this afternoon.
"He's not had a battle this year but this was a proper race and that showed his class".
Owner JP McManus is responsible for Irish Gold Cup victor Edwulf (Joseph O'Brien), last year's runner-up Minella Rocco (Jonjo O'Neill) and Anibale Fly (Tony Martin). I'm thrilled as Barry missed out last year and whilst Noel gave him a great ride last year, it was nice that Barry was involved and got to share in it and enjoy it.
Racing fans from the Emerald Isle are also playing for much higher stakes than their United Kingdom counterparts.
"It's going to be fun, it's got to be, otherwise we wouldn't be doing it". The ground made it the ultimate test.
Four horses died in last year's festival.
Rather boringly, Elliott's top boy for the big occasion is now going for the same race he won a year ago, the Cross Country Chase (4.10), and I fancy him to go well again when it matters before going on to Aintree for the Grand National, in which he finished runner-up last April. "He really dug deep and was a scrapper today".