Zarkandar came late and fast under Daryl Jacob to land the Triumph Hurdle on only his second start over hurdles.
Paul Nicholls' gelding, a half brother to the brilliant Zarkava, was always travelling sweetly in midfield and began to cut through the pack as they turned for home.
Two from home it looked as if Grandouet and Barry Geraghty were going best as they cruised into the lead.
But approaching the last it was Zarkandar (13-2) who was in full flight and a great jump put him in total control.
He powered up the hill to beat the running on Unaccompanied by two and a quarter lengths, with the tiring Grandouet (13-2) just hanging on for third from the fast finishing favourite Sam Winner (4-1) who got badly outpaced at half-way.
The winning jockey said: "I have to thank the owners for keeping me on him after he'd won the last day.
"He took me into the race so easy. I was very impressed with him the last day and he is very tough."
Nicholls added: "I loved him the first time I saw him at the Aga Khan's sale but he was very difficult when he first arrived and he was a challenge.
"I felt he was next year's horse but I'm delighted. He'll be some horse with another summer on his back.
"I am pleased to provide a winner for Daryl Jacob - he's worked so hard and just missed out on a few winners this week."
