The Whites earned a dominant 1-0 victory over the Hornets at Elland Road on Saturday afternoon, the club's first Premier League victory of the season under head coach Marcelo Bielsa.
Diego Llorente's 18th minute strike was enough to claim all three points though the fixture threw up controversy.
Leeds were denied a penalty by on-pitch referee Simon Hooper and VAR official Lee Mason shortly after taking the lead in West Yorkshire.
Winger Dan James was hauled to the floor by visiting defender William Troost-Ekong as he burst into the box to chase the ball but home protests were waved away.
Watford then saw a goal chalked off in the second half after United goalkeeper Illan Meslier dropped a corner into his own net via Liam Cooper' s back.
The whistle was blown with the ball crossing the line - meaning VAR couldn't intervene - following a tangle between the Leeds skipper and substitute Christian Kabasele.
Replays showed the pair had both been grappling each other but the decision went the way of Leeds and Meslier's goal survived the rest of the encounter relatively untroubled.
The decision, which has split opinion among football supporters, has now been backed by former man in the middle Gallagher.
"I think you need to watch it carefully," he told Sky Sports over the decision to disallow the Watford goal.
"When it happened on Saturday and ended up in the net, my immediate reaction was that the goalkeeper had dropped the ball and the tangle between Kabasele and Cooper had no impact on the goal.
"When you look at it, it does - because when they fall it actually strikes Cooper's back and goes into the goal.
"There's a tangle between the two players and because of that it puts the ball into the net and that's why the referee is forced to disallow the goal. He feels Kabasele has dragged Cooper down.
"There's no doubt they're grabbing each other and it has impacted it - it's gone in off Cooper.
"It strikes him and goes in, so you can't ignore that. He blew his whistle when the ball came across before it went in the net.
"The referee felt Kabasele was more of a fouler than Cooper, if you like. I think it was right to disallow it.
"When I saw what happened with Cooper I changed my mind. My instinct was that the goalkeeper had dropped the ball but when I saw the replay it followed on."
Ex-Leeds captain Stephen Warnock, who attended the game in LS11, disagreed with the ex-top flight match official's verdict.
"I thought it was a goal," Warnock said.
"I think there's enough of a 50-50 challenge between the two players going after each other to just say get on with the challenge between you. I think Leeds and Cooper are lucky.
"Even when Cooper gets up there isn't a complaint from him to say he's been dragged down. It's both ways and they know it."
We’ve gathered the best of today’s Premier League chatter below...