Nicky Henderson's Whisper saw off At Fishers Cross on the run-in to land the Silver Cross Stayers' Hurdle at Aintree.
At Fishers Cross was the 11/8 favourite following a fine third in the World Hurdle at Cheltenham, with Whisper a 4/1 shot, graduating from handicap company following success in the Coral Cup.
At Fishers Cross and Zarkandar disputed the lead from flag-fall and while Zarkandar dropped away tamely in the straight, to his credit, the market leader stuck to his guns.
However, Barry Geraghty was soon in his slipstream aboard Whisper, who set off bathed in sweat, and after a brief battle after the final flight, the Seven Barrows runner won the argument by a length.
At Fishers Cross was not disgraced given he jumped out to his right for much of the extended three-mile journey.
Having looked likely to be tailed off at one stage, admirable grey Thousand Stars made late headway to pick up minor honours in third.
Geraghty said: "He got himself into a bit of state beforehand and was over-hyped and over-revved and I thought for most of the way I had no chance, but he does stay.
"At Fishers Cross is hard to pass and even when I did I thought I was in trouble again, but in fairness to my lad, and considering the state he was in, he didn't give up and stayed really well."
Sky Bet introduced the winner at 10/1 for the World Hurdle and spokesman Michael Shinners said: "It was a really gutsy performance for this highly progressive Nicky Henderson runner. He proved that he stays the three-mile trip and is an interesting contender for next year's Ladbrokes World Hurdle."