Chris Smalling has not completed a full season for Manchester United yet but he is already acutely aware the inter-city rivalry up north is far more intense than he was used to in London.
The former Fulham man knew all about battles between the capital clubs and the passions they can create. But none of them quite compare with what he will experience on Sunday, as 90,000 supporters of Manchester's big two descend on Wembley, split down the middle between red and blue.
"The rivalry is more intense than it is down south," said the England Under-21 star. "There are a lot more clubs around London. Around Manchester you are either one or the other - and you need to choose wisely. I have really enjoyed it because I am right in the thick of it. Where I live, people either support City or United. I feel as though I have been dropped into a real rivalry."
Smalling accepts he will start Saturday's encounter on the bench if Rio Ferdinand declares a determination to play. Yet even that would bring a sense of excitement for a player who just over three years ago was learning his trade in the non-league with Maidstone.
And, as a Premier League encounter with Newcastle looming on Tuesday, Smalling hopes to play some part in the coming days.
"It was brilliant for me to play in the last derby," he said. "To play in a semi-final at Wembley would be a dream come true. Not many players get the chance to do it in their entire careers. To be involved in one at my age would be beyond my wildest imagination.
"I realise it might not happen but, bearing in mind, we have a midweek game in the league at Newcastle, it would be nice to play in one of those just to keep my run going."
Central defence is just one area where Sir Alex Ferguson faces a tricky selection dilemma. Midfield is an equally thorny problem, with Paul Scholes, Anderson and Darron Gibson all hoping for central roles after missing the Champions League triumph over Chelsea.
Antonio Valencia can expect to start on the right wing, with 22-goal Dimitar Berbatov likely to be handed a striking slot given Wayne Rooney is completing a two-match suspension.