Manchester United boss Sir Alex Ferguson has dismissed criticism from Manchester City over his decision to bring Paul Scholes out of retirement.
Ex-City midfielder Patrick Vieira said the move showed "weakness".
But Ferguson warned he "had plenty of ammunition" if United's title rivals wanted to engage in mind games.
"If it's desperation bringing back the best midfielder in Britain for the last 20 years then I think we can accept that," said Ferguson.
Vieira, City's football development executive, told the Daily Telegraph on Wednesday: "For him [Scholes] to come back just shows a little bit of weakness in United, because they had to bring a player back who was 37."
United have won nine Premier League games and drawn one with Scholes in the team, and Ferguson responded in the week when City boss Roberto Mancini controversially recalled striker Carlos Tevez.
"I think he [Vieira] was programmed for that," said Ferguson.
"Roberto had a wee dig a couple of weeks back. We're all going to play our hand that way. There will be plenty of ammunition for that.
"If you talk about desperation, they played a player the other night who refused to go on the pitch. The manager said he'd never play again and he takes a five-month holiday in Argentina. What is that? Could that come under the description of desperation?"
Tevez denied that he refused to come on as a substitute in a Champions League game against Bayern Munich in September, blaming "confusion on the bench" for the "misunderstanding" which led to a major falling-out with Mancini.
The Argentine returned for the first time in six months in Wednesday's 2-1 victory over Chelsea which leaves City one point behind leaders United with nine games of the season remaining.
Ferguson also rejected Vieira's assertion that a further sign of United struggling was their inability to keep Ravel Morrison, who joined West Ham during the January transfer window, and their ongoing fight to retain fellow midfielder Paul Pogba.
"The point he made about Ravel Morrison and losing our young players - we wanted to sell him (Morrison) let's be clear about that, for obvious reasons," said Ferguson.
"But we want Pogba to stay because we think he's going to be a fantastic Manchester United player and hopefully that's the case."
Since moving to London, Morrison has been fined £7,000 by the FA and warned about his future conduct after a homophobic post on social networking site Twitter.
Ferguson's comments come after United defender Rio Ferdinand suggested City fans are only more visible now the club is tasting success.
"Walking around in town, you see more and more blue shirts than you probably ever would have seen over the last 10 years," the defender told BBC Sport.
"Success sometimes brings people out of the woodwork."