City's Mancini did not back down as Ferguson delivered some Glasgow invective in his direction after tempers became frayed with the feisty Scotsman's side looking desperate at 1-0 down, much like his team in recent weeks.
Ferguson blamed Mancini for the touchline spat, accusing the Italian of "badgering" the officials, while his opposite number put it down to the "tension" of the occasion after his side had taken the spoils with a Vincent Kompany goal.
After handshakes were offered and accepted and the dust settled, however, it was Mancini who clearly won the tactical battle against arguably Britain's greatest ever manager.
City, eight points adrift after the Easter fixtures having been in charge for so long, seemed to have had their title dreams shattered but they have dragged themselves back to the summit on goal difference with two games remaining and are within sight of a first title since 1968.
United, bidding for a record 20th English crown, have stumbled, losing at Wigan Athletic and then throwing away a 4-2 lead against Everton last weekend.
They still boasted a three-point lead before kick-off on Monday but were strangely subdued and barely tested City's England keeper Joe Hart as the team Ferguson once labelled the "noisy neighbours" seized the title initiative with a priceless 1-0 victory to seal a league double over their arch rivals.
Mancini expressed some surprise at United's cautious approach although admitting the job was far from complete.
"It's a great victory but we have two difficult games left and United have two easy games," said Mancini, whose side face fifth-placed Newcastle United this weekend before a final home game against strugglers Queens Park Rangers.
"United are still favourites. [United's opponents] Swansea and Sunderland have nothing to play for. I am very happy that we are top but it doesn't change anything.
"United put all their players behind the ball and only one striker. They wanted the draw. They played a different game to usual. We deserved to win."
FEW CHANCES
Ferguson, who began with Wayne Rooney as a lone striker, said his side underperformed and the title was now in City's hands.
"It was feisty and competitive as we expected and there were not a lot of goal chances," Ferguson told Sky Sports. "David de Gea only had one save to make but I'm disappointed we never tested their goalkeeper to be honest.
"It was a damaging result, they are in the driving seat and we are up against it. They only need to win two more games and they win the league, simple as that.
"It's not over yet, of course it's not over, there is still football to play. But the situation is that they have an eight goal advantage which is a big advantage at this stage."
After a bright start United played second fiddle as City upped the tempo and began to dominate possession with former United striker Carlos Tevez driving his side forward.
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