Messire Des Obeaux was worn down by Keeper Hill in the home straight at Huntingdon to beat his major rival by a neck at the line in the Listed Sidney Banks Memorial Novices' Hurdle.
Keeper Hill is quoted at a best-priced 20-1 (down from 33-1) for the Neptune Hurdle at Cheltenham in March.
Gavin Sheehan rode a great race as he increased the tempo throughout to pressure favourite Messire Des Obeaux, who was conceding an 8lb penalty to his five rivals.
Trainer Warren Greatrex said: "Keeper Hill did everything wrong and still found a way to win. He's got a lot of talent and is still very raw and we'll have a look at the Neptune after that.''
Alan King, trainer of runner-up Messire Des Obeaux, added: "He lost nothing in defeat and the Neptune remains the plan. This was just a prep and this wasn't his track."