Sir Alex Ferguson fired a warning shot at Manchester City as the Manchester United manager claimed he has "plenty of ammunition" if Roberto Mancini's men want to play mind games.
Ferguson has been infuriated by comments from Patrick Vieira, City's football development executive, who this week said the United boss's decision to bring Paul Scholes out of retirement was a sign of desperation.
Former City and Arsenal midfielder Vieira was shocked that Ferguson turned to Scholes to bolster his midfield in January after the 37-year-old spent several months in retirement.
Vieira further angered Ferguson by questioning United's chances of competing with City in the long-term because of their inability to hold onto young players, citing the recent sale of talented but troubled forward Ravel Morrison to West Ham.
Ferguson believes Vieira's comments, as well as some made recently by City manager Mancini, constitute the kind of mind games aimed at destabilising their rivals which the Scot himself has excelled at throughout his reign.
City closed the gap on leaders United to one point with a win over Chelsea on Wednesday, setting up the prospect of an explosive title battle.
And Ferguson poured fuel on the fire as he took the chance to hit back at City in a week when Carlos Tevez made his controversial return to Mancini's team six months after he refused to warm-up during a Champions League game at Bayern Munich.
"If it's desperation bringing back the best midfield player in Britain over the last 20 years then I think we can accept that," Ferguson said on Friday.
"I think he (Vieira) was programmed for that. I think Roberto had a little dig a couple of weeks back.
"We're all going to play our hand that way. I've got plenty of ammunition for that.
"The point he makes about Ravel Morrison, losing our young players, we wanted to sell Ravel Morrison, let's be clear about that, for obvious reasons.
"But we want Paul Pogba to stay because we think he is going to be a fantastic Manchester United player and hopefully that's the case.
"If you're talking desperation, they were playing a player the other night who refused to go on the pitch and the manager said he'll never play again.
"He takes a five-month holiday in Argentina. What is that? Could that come under the description 'desperation?'
"I've got plenty of ammuntion, don't worry. They can try."
Ferguson's comments serve to underline the growing tension between the Manchester rivals as they compete for the title.
However, the claim that using Scholes was an act of desperation does appear to ring hollow given that he has won eight and drawn one of the nine league games in which he has been involved since his return in January.
"He's useless," joked Ferguson. "What he does is he can dictate the tempo of a match.
"That experience helps, of course, and he has a terrific football brain which helps him.
"The amazing thing is he made the decision he made at the time simply because he didn't want to play 25 games. He wanted to play 50 games, that's the reason he wanted to retire.
"I said to him at the time, you can play 25 games no problem but he didn't want that.
"He felt he didn't have enough appreciation but what I was trying to do was look at it sensibly and what you can get out of a 37-year-old."
Ferguson's side could be knocked off the top if City win at Stoke on Saturday, but they will return to pole position with a victory against Fulham at Old Trafford on Monday.
Apart from Nani and Michael Owen, Ferguson has a fully fit first team squad from which to select as he prepares for Fulham's visit.
"That happens," he added. "You get that when it comes to the crucial part of the season, everyone tends to get fit again.
"I'm delighted, of course, because having a full squad like that gives me variety."