Henderson has now secured six victories in the two-mile showpiece and, just for good measure, he also saddled runner-up My Tent Or Yours, who was finishing second in the race for a third time.
The first two horses home are owned by JP McManus, with Buveur D’Air’s four-and-a-half-length verdict achieved under the expert guidance of Noel Fehily.
Henderson said of the 4-1 winner, who was third in the Supreme Novices’ Hurdle 12 months ago and had been chasing this year: “He’s not very flashy at home, but you had to feel that there was unfinished business (over hurdles).
“There wasn’t a particular moment when I thought we should go back to hurdles but he’d only run four times. I just felt he had unfinished business over them.
“I think he could still go back chasing one day. “It was a very open race, but I just knew he was a very talented horse.”
Of My Tent Or Yours, the trainer added: “He’s just sensational, but the young horse has done it. You feel sorry for My Tent Or Yours. It’s wonderful we’ve won the Champion Hurdle but that’s three Champion Hurdles he’s been second in. What else can you say about him?”
Henderson admitted earlier that the pressure was already off as the exceptionally good Altior won the Racing Post Arkle Challenge Trophy as the 1-4 favourite.
The Seven Barrows handler is keen to see his charge in action again this season, with Sandown the likely destination, and is already looking forward to a potentially mouthwatering clash with Douvan next term.
“That was the one horse that had to win,” said Henderson.
If Henderson had a memorable afternoon, Gordon Elliott had a scarcely believable one with a first-day treble.
Elliott’s most significant winner came in the OLBG Mares’ Hurdle when Apple’s Jade (7-2) showed true grit to deny the Willie Mullins-trained Vroum Vroum Mag and Limini
“Today was her Gold Cup,” said the County Meath handler.
“She will stay three miles next year. I would imagine we will go to Punchestown.”
Elliott earlier pocketed the curtain-raising Sky Bet Supreme Novices’ Hurdle with 25-1 shot Labaik, who has rarely started a race this season, let alone win one, but did enough to foil the Mullins hotpot, Melon.
The trainer said: “I don’t care if he never jumps off again!”
Elliott was back on top after the JT McNamara National Hunt Challenge Cup Amateur Riders’ Novices’ Chase as the unheralded Lisa O’Neill steered Tiger Roll to glory at odds of 16-1.
“Lisa is an absolute star and it’s been an amazing day,” added the Cullentra House trainer.
“I can’t believe it. To train three winners on the first day of Cheltenham…I thought if I had one this year I’d be delighted.
“It’s a credit to the staff I have at home and the owners and the horses. It’s brilliant.”
Un Temps Pour Tout (9-1) was gameness personified to win back-to-back renewals of the Ultima Handicap Chase for David Pipe and Tom Scudamore, while Tully East came out on top for Alan Fleming and Denis O’Regan in the Close Brothers Novices’ Handicap Chase.
But for Mullins it was an afternoon to forget as the Closutton handler struck out on the first day of the Festival for the first time since 2008.