Mancini accuses Rooney of getting Kompany sent off

City claim United striker influenced referee, but Ferguson says tackle was dangerous

The Manchester City manager, Roberto Mancini, last night accused Wayne Rooney of attempting to influence referee Chris Foy's decision to dismiss City's captain, Vincent Kompany – the pivotal moment as Manchester United knocked out the FA Cup holders and progressed to a potentially inflammatory fourth-round encounter at Liverpool.

Mancini, who also declared that his 10-man side's second-half performance demonstrated beyond all doubt that they were capable of beating United to the title, offered a prickly reply to his counterpart Sir Alex Ferguson's claim that Kompany has a history of two-footed challenges. The Italian said that Rio Ferdinand and United's defenders were frequently guilty of the same offence, though it was Rooney's gesture, appearing to wave an imaginary red card, after Kompany's 11th-minute challenge on Nani which angered Mancini – who will now be without his captain for four games unless City's appeal is successful.

"Rooney told [Foy] his decision. He influenced the referee," said Mancini. "[Rooney] was near the referee. Yes [he influenced the decision]." Mancini, already without Kolo Touré because of the African Cup of Nations, confirmed City would appeal but if the dismissal is upheld and the appeal is deemed a deliberate attempt to delay suspension, the ban – already extended to four games because Kompany was sent off earlier this season – would total five games. He will miss both Carling Cup semi-final ties with Liverpool and the League game with Tottenham.

United, meanwhile, face Liverpool twice in 17 days, and could encounter Luis Suarez if their fourth-round tie with Kenny Dalglish's side goes to an Old Trafford replay.

Mancini, who apologised last Tuesday after gesturing to the referee that Liverpool's Martin Skrtel should be dismissed in City's 3-0 Premier League win, could take huge encouragement from the second half. He pointed out that his own 10-man side had not collapsed as United's did at old Trafford in October.

"When United played with 10 men for 40 minutes they lost 6-1," he said. "We played for 80 minutes with 10 players and didn't concede any chances in the second half. We knew it was not impossible but it was very difficult to score three goals. We had a chance. United didn't have any chances in the second half. This performance is important for us for the League. I think now we can win the League [because of the character we showed]. United is the top squad in England and if we can play like we did against them for 80 minutes with 10 men with that same strength and attitude in every game, we will win the League." It was by far the firmest assertion yet from Mancini that they can depose United as champions.

Ferguson was as indignant about Kompany as he was about Foy's refusal of a penalty for Aleksandar Kolarov's second-half challenge on Antonio Valencia – which saw him manhandle Foy as he left the pitch. "I have seen [Kompany] do it before. He has got away with it before," Ferguson said. "If there had been contact with Nani then it would have been a bad one. The referee was right on that one."

Though the victory removes the pressure from a United seeking to avoid their first three-game losing run in 11 years, he rounded on his players for carelessness which, he said, had spared City a "battering". Ferguson said: "We made them better than they were. We were careless in the second half. We took our foot off the pedal. They waited for us to make mistakes and we made them. It made it in to a scoreline that it shouldn't have been."

Despite Rooney's two goals, he was a shadow of Sergio Aguero in the second half and Ferguson said last night that his behaviour would be hyper-analysed. "It is the situation that existed many years ago with Paul Gascoigne," the manager suggested. "We have seen the good stuff today. There is no problem with the boy's temperament at all. It is just off the field he is going to be spotlighted all the time."

Of the decision to hand Paul Scholes a contract to play until the end of this season, Ferguson said: "Paul has been training very hard with the reserves and doing a lot of work in the gym. He came to see me and said I regret retiring. There are no negatives for me."