Aubusson could now embark on a chasing career after being denied by the narrowest of margins in the Grade One Prix D'Automne at Auteuil last Saturday.
The six-year-old was one of the outsiders in the 10-runner race but he was just denied by veteran Thousand Stars, who swooped in the final stride to lift the prize by a nose
Williams is now deliberating whether to stay over hurdles or switch Aubusson's attentions to fences.
"It was agonising to come so close, it must have only been half an inch," he said.
"I've seen the photo and I couldn't split them myself. I think I'd have preferred to have been beaten two lengths.
"He was an outsider, so he's massively outrun his odds, but it's still hard to not think 'what if'.
"On the ratings he still hasn't run to the mark off which he won the Fixed Brush Hurdle at Haydock last season.
"I'm not sure what we'll do now, just reflect a bit - chasing is a possibility as he's got so much size and scope."
Williams also ran the 2013 victor Reve De Sivola and he was not beaten all that far back in sixth, just behind David Pipe's Broadway Buffalo.
"I think when he won it he got very lucky, he was only eighth jumping the last," said Williams.
"I'm not sure Auteuil really suits him, but he'll go straight to the Long Walk at Ascot now.
"That's his race. He's going for his fourth win in it and everything just seems to fall right for him there, soft ground and a small field."
