Reve De Sivola was all out to hang on from Oscar Whisky in a pulsating Rewards4Racing Cleeve Hurdle.
The eventual winner was always prominent, with in contrast Geraghty sat waiting as long as he could to preserve the runner-up's unproven stamina.
Richard Johnson and the Nick Williams-trained Reve De Sivola edged clear of gallant leader Knockara Beau after two out, but it was at the last that Geraghty looked like he might have timed matters to absolute perfection.
The pair settled down to fight it out and Long Walk winner Reve De Sivola (15-8 favourite) would not give in, sticking his neck out get the verdict by a neck, with third home Kentford Grey Lady six lengths further back.
Johnson said: "He's got a very big heart. To be fair the owner said he wanted better ground. After Ascot I wasn't sure, but today he probably didn't enjoy it as much. He still toughed it out really well and it was a good performance.
"I had a little look turning in and I knew Barry (Geraghty on Oscar Whisky) was there.
"When he came to me this fella put his head down and he wants to win."
Williams said: "His win at Ascot was the best three-mile performance without Big Buck's so I was quite confident coming here.
"The World Hurdle has to be our next step, as we need three miles and he doesn't have to have this sort of ground, although he wouldn't want it very quick."
Henderson said of Oscar Whisky, who was having just his second try at the three-mile trip: "No-one can say he didn't stay, he might want better ground and you could say he might not possibly now have to be ridden to get the trip.
"We have always had Aintree (two-and-a-half-mile Aintree Hurdle, of which he is a dual winner) as one of his races, but those were the best three-milers apart from Big Buck's and you might say that you have got to try three miles back here again (in March).
"If it came up soft there's still the Champion, and it's something that Dai (Walters, owner) and I have got to discuss."