Although the betting suggested the race would be a penalty kick, it proved to be anything but that, with the seven-year-old forced to battle like he has never done before to defend his title in the highlight on day one of the 2018 Festival.
With little to separate the pair on the climb to the line, it was only in the dying strides that the 4-6 favourite and Barry Geraghty got the better of the battle to emerge victorious by a neck, with Mick Jazz a further three lengths back in third.
In doing so, Buveur D'Air became the first horse to retain his Cheltenham crown since Hardy Eustace in 2005.
Henderson, celebrating his seventh Champion Hurdle victory, said: "It was a good race, a proper race. They've gone some gallop and we've set it (with Charli Parcs). I couldn't believe they would keep that gallop up the whole way and they have. Once they've taken it off the front two, they have still kept at it. Barry said he was always happy.
"The second horse is a good horse, I don't think there is any doubt about that. It's the first time he has had a race all season (after three easy wins) and that did worry me, I must admit. The ground was never a worry.
"He had a good blow, as he simply hasn't had to knuckle down before. It was job done. He is a young horse and he has done everything right the whole way.
"Even if they thought it was a penalty kick, he got a battle, but he did what he had to do. He probably was a neck down, but once Barry said 'come on, we've got to go' he put his head down and knew exactly what he was doing.
"That is a big relief, you are expected to collect and he has done. It's a relief it is over."
Looking to future plans, Henderson said: "He can run again and we have four weeks until Aintree. I've not had a talk to JP to see what anybody wants to do, but as long as there's some soft ground around (he could run)."
Having missed the ride through injury last year, Geraghty was delighted to be be back on board this time round.
He said: "I could feel with my fellow that the further he was going, the better he was finishing. I was happy how I popped the last and there was no rush, even from there. He is a true champion.
"He's very good - you don't win them back-to-back unless you are very good. He's a top-class horse.
"I missed last season and it's nice to ride a big winner for the boss (McManus) and doubly to do it for Nicky.
"It was a long year last year, but I've had great years here so I can't complain."
A rematch could be on the cards, with Willie Mullins keen to send the runner-up on a retrieval mission to Aintree.
He said: "I'm delighted with him, as it's vindicated what we have always thought about him. Last time we put the hood on to help him settle, but he didn't enjoy that at all.
"Probably I'd say we'll keep him hurdling next year and I'd imagine he'll go to Punchestown, but he could go to Aintree over two and a half (miles), we'll see."
Faugheen passed the post a well-beaten sixth and a likely step up in distance awaits the multiple Grade One winner.
Mullins added: "Ruby (Walsh) said Faugheen just wants a longer trip nowadays, he just lacks the spark for two miles.
"He'll be campaigned at those staying trips now so we'll probably go out in trip at Punchestown or maybe look at the race in Aintree."
The Mullins-trained Yorkhill was even more disappointing, eventually pulling up.
Mullins continued: "Yorkhill is just not performing, it's a real head scratcher, sometimes horses take a year out.
"We've been up and down in trip, over fences and hurdles - we'll see where we go from here.
"There's not much more to say."