The visitors were leading 1-0 courtesy of a Robin van Persie header, his 18th Barclays Premier League goal this season, when substitute Wayne Rooney went down under a challenge from Steven Caulker inside the box.
Referee Chris Foy declined to award a spot-kick, and Spurs, who dominated the second half, netted a dramatic 92nd-minute equaliser through Clint Dempsey.
The draw cut United's lead over Manchester City from seven points to five at the top of the table, and Ferguson was blunt in his views about assistant referee Simon Beck after the game.
"It was definitely a penalty. He has put his leg right in there," he said.
"The linesman is facing it – I thought he had a very poor game, the linesman. I thought he was disappointing.
"We have got that history with him. He never gave offside with (former Chelsea striker Didier) Drogba at Old Trafford when he was three yards off. Everyone remembers that – I certainly do."
The incident with Drogba came in a 2-1 Chelsea win at Old Trafford in April 2010 and Ferguson felt his side had been let down again yesterday, with Rooney seemingly fouled only moments after coming on for Shinji Kagawa.
Ferguson added: "For me it was a poor performance from him, why he never gave a penalty I don't know.
"I think he had a shocking game. We never got anything from that side of the pitch."
Spurs boss Andre Villas-Boas was unsure whether Caulker had caught Rooney, but did not want the argument to overshadow a tremendous performance and hard-fought point for his side.
He said: "It is going to be debated and debated and I hope it doesn't mar the game.
"During the game we got most of the decisions against us. I prefer to look at this game from my view and United prefer to look at it in their view.
"We will take our boost in confidence but the debate is going to be whether it was a penalty because that is controversy and sells better, but we should not mar the game and quality of the game played in these difficult conditions.
"Fortunately we got a point. It is credit for the game that we had. We were the best team and created the best chances.
"I think it was probably the worst United game in terms of opportunities, with them having only four. It is a pity we couldn't win but I'm happy with the draw obviously.
"I'm not sure (who will win the league) but United have the experience that can help."