Manchester: Angel di Maria, Manchester United’s vibrant attacker, warned his Argentine friends in the City camp ahead of Sunday’s Manchester derby that there are “no friendships out on the pitch”.

Di Maria, United’s No.7, said: “You are defending the pride of your colours.”

A quarter of Argentina’s World Cup outfield contingent could be involved at the Etihad. Along with his United teammate Marcos Rojo, Di Maria knows Pablo Zabaleta, Sergio Aguero and Martin Demichelis well.

“We’ve got good friendships over the years and no matter what the colour of your shirt, you still see each other socially,’’ said Di Maria. “But once you’re on the field, you forget all that. Everyone is fighting for the shirt.”

Friends for life, but rivals for 90 minutes, will embrace beforehand. “When we see each other in the tunnel before games, I think it’s right to say ‘Hi’ and greet each other - whether it’s an ex-teammate or a good friend,” Di Maria added. “That’s normal, as long as you remember that you fight for the club and the shirt once the 90 minutes start.”

Zabaleta smiled wanly at the mention that he is likely to be facing Di Maria. “It’s tough, hard,” said the City right-back. “He’s a really good player, quick with great technique. He’s one of those players that defenders find really difficult to play against. You need the perfect day to stop players like him. I will try to play as good as I can.”

Zabaleta, Di Maria and Rojo turned coaches for the afternoon on Friday, helping out a Premier League Kicks session at Manchester College, Ardwick. With the derby looming, the emphasis was on a city united. Di Maria flicked balls up for youngsters from the City in the Community scheme to practise their finishing and congratulated them warmly when they scored.

Zabaleta did the same with kids from the Manchester United Foundation. As a local in an Argentina shirt looked on transfixed, Rojo rolled the ball into the path of City youngsters. “When we do things like this, especially with the kids, it’s great to see the relationship between both clubs,” Zabaleta said.

“We know about the rivalry. For fans this is the game they are looking for. Two big clubs in the same city, big rivals. This is the special game for the fans, so we will try 100 per cent to win to let the fans celebrate.”

Having arrived six years ago, Zabaleta knows the city well, so well that Di Maria got in touch with him for some local knowledge when considering United’s offer while at Real Madrid in August. “Angel texted me to ask about the city, to ask things of someone who has been living here for a long time, so I could help with some information.”

Di Maria said nobody at City, not even friends such as Zabaleta, Aguero or Demichelis, tried to tempt him to the Etihad. “No, there was never any contact anywhere else,” Di Maria said. “The people who came with all the paperwork, signed and ready, showing real eagerness to sign me were United. As soon as I heard of their interest, there was no question of me going anywhere else.

“As a player, you’re always going to go somewhere if the club really want to sign you and show willing by putting that amount of money on the table. I think the figure was 75 million pounds. It would be hard for any club to turn that down - even Real Madrid. I felt from the word go that I was going somewhere where I’d be really loved. I’m not saying that I wasn’t loved in Madrid - but that kind of interest that Manchester United showed is hard to turn down.”

He was also indebted to Louis van Gaal. “It was him who showed that confidence in me by wanting to sign me,” Di Maria said. Having enjoyed Di Maria’s company on the 3G pitch in Ardwick, Zabaleta was looking forward to seeing his friend again - after Sunday’s game.

“We’ve known each for many years,” Zabaleta said. “I was so happy when he signed for United because he was really excited to come here and play in the Premier League. When I see him happy, I will be happy as well - off the field.

“He’s been busy so it has been difficult to meet. He lives in Prestbury, I live in Alderley Edge, just five minutes away. Marcos lives in Hale, a little bit far from where we are. Kun has moved to Hale now. When everything is settled we will all get together. We’re Argentinians, we like to meet each other, to do barbecues. I’m thinking now of opening an Argentinian restaurant!”

He has not tried to persuade Di Maria of the joys of English fish and chips. “Not yet. He’s that thin. Probably he will try it.”

— The Telegraph Group Limited, London 2014