Harry Redknapp called for video technology to be introduced after two controversial goals helped Chelsea beat Tottenham at Stamford Bridge.
Salomon Kalou poked home a late winner for the hosts from a borderline offside position, after Frank Lampard had earlier cancelled out Sandro's spectacular opener with an effort that squirmed under Heurelho Gomes.
Although the Brazilian goalkeeper appeared to prevent the whole of the ball crossing the line, the assistant referee awarded the goal amid howls of protest from Spurs' players.
Redknapp told Sky Sports: "The first one wasn't over the line and the second I thought was offside.
"That [the first goal] changed the game. The linesman's made a mistake - an honest mistake. He's had an honest guess, but he's guessed wrong.
"It's the most difficult thing in the world to see from where he was - he was probably on the 18-yard box when the ball dropped on the line, and he's given what he thought was the right decision.
"But technology's got to come in. That took seconds to see it, five seconds just to go, 'Yes it's a goal; no it's not a goal'. You get a fair decision, the game moves on.
"I don't see why we're still messing around after all these years and haven't got technology in the game. It's amazing."
Redknapp also defended Gomes following his error on the first goal, saying: "He's a great goalkeeper. I don't know what happened with that first one, I though he had it covered and obviously it's slipped through his hands. But he doesn't worry me."
Opposite number Carlo Ancelotti echoed Redknapp's view that it is time for technology to be introduced.
"Unfortunately the referee does not have a television and I think technology for the goal could be a good decision," he said.
"It was not an easy decision, in my opinion."
Asked if they had been lucky, Lampard told Sky Sports: "In those two instances, maybe yes.
"The one that didn't go over the line, I was due one of those - I had a big one [at the World Cup] in the summer! So I'm pleased with that. But it's unlucky on them.
"You get what you deserve and, that's not rubbing it in on Tottenham, we deserved that, we created enough, we were bright enough to win the game."
Chelsea are now three points behind United, who have that game in hand against Arsenal to come, and Lampard hailed the spirit of his side.
He said: "We're fighting to the end. We had a couple of months where we let ourselves down a bit and let it slip, but you saw the character. We deserved it.
"They're in the driving seat and it's theirs to lose, but if they do slip up we're in a position now where we'll have a real go to try and do it.
"We've kept ourselves alive and we can sit back and watch and hope."
Chelsea skipper John Terry felt the result said a lot about the character of the team following their mid-season slump.
"We said a few weeks ago when we were nine, 12 points behind that the one thing about Chelsea is we never give up," Terry said. "That's what we're all about.
"Man United have said in the week that we're their biggest challengers and they've got a massive game that they must win to open up that gap again."
