"I think Mike Dean went over to the assistant linesman to ask whether Gallas had touched the ball. The assistant obviously said, 'No he didn't'."
But Hughes insisted Gallas' very presence in front of goalkeeper Mark Schwarzer should have been enough for the goal to have been chalked off for interference.
He said: "Mark Schwarzer has to hold his position until the ball actually reaches where Gallas is, because he's thinking at some point Gallas may stick a toe out and deflect it.
"To say he's not interfering or not in his eyeline is completely at odds with the truth."
Hughes also suggested Dean had been prompted to challenge Yerby's original decision by Huddlestone and his team-mates.
"I think Huddlestone went over," Hughes said.
"He was the first to get into Mike Dean's face and obviously made a compelling argument."
"I'd like a little bit of clarification," said Hughes before learning Dean had already left the stadium.
"If he's made a genuine mistake, he'll admit to it, but it doesn't do us any good so what's the point?"
Ref got goal right - Huddlestone
Meanwhile, Spurs boss Harry Redknapp admitted Gallas had been "maybe a foot offside" when Huddlestone shot.
He went on: "It's very rare to see a change when the linesman puts his flag up. You thought 'that's it, he's given offside'."
Reflecting on the match as a whole, Redknapp added: "It's the third time this year we've come from behind to win. It shows a lot of character we have in the team that we can come from behind and still win games."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.