Ruby Walsh believes any questions over Vautour's stamina can only be answered if he runs in the Timico Cheltenham Gold Cup.
A winner at the last two Festivals over two miles and an extended two and a half, he was beaten in a photo-finish to the King George VI Chase over three miles at Kempton.
Some suggested a lack of stamina was to blame for that eclipse, but Walsh felt the evidence was inconclusive, although he is certain Vautour is better on a left-handed track.
"I thought he ran a blinder," he told Racing UK.
"He jumped a little to his left and if I was to ride it again, I probably would have sat a little bit longer on the bend going to the third-last, but I rode him according to the feel he was giving me.
"I thought I had plenty of horse left to go and win the race from there, but Cue Card found plenty for pressure and chinned me.
"I don't think Vautour lost a whole pile in defeat, it was a huge improvement on his Ascot run and it's onwards and upwards.
"You'd have to think he'd be better at Cheltenham. He did jump a little to his left, nothing too bad to throw it away, but just a fraction so you'd imagine left-handed would be an advantage.
"I think he did stay as a couple of strides after the line he was back in front.
"Whether he'll get three and a quarter, I don't think you can answer that question until you try it."