Some of Man United's hardened supporters may have received a shock on Sunday when striker Robin van Persie celebrated a Man City victory.
The Dutch striker's son plays for City's under-9 team, and he leaped into the air with joy when they secured a victory at his youth tournament in Maassluis, Holland.
Named the 'Robin van Persie International Tournament,' it was set up by the striker to raise funds for the Sophia Children's Hospital in Rotterdam.
The event featured 14 teams from around the globe including City, Chelsea and Tottenham Hotspur.
Emile Heskey and Darren Fletcher, whose son also plays for City's youth team, were also present to see Feneyoord lift the trophy.
Robin van Persie will not be taking penalties for Manchester United anytime soon, Louis van Gaal has confirmed.
The Dutch striker missed a vital spot-kick in his side's weekend loss to West Brom.
"No, he is now at the end of the road," the United boss said when asked if Van Persie would continue taking penalties.
"It is always (like that). Wayne has missed also so when you miss you are at the bottom again."
Louis van Gaal has confirmed that striker Robin van Persie is an injury doubt for Saturday's Premier League clash at QPR.
Van Persie is struggling with the ankle injury that forced him off during last weekend's defeat to Southampton, and will be assessed by United's medical staff tomorrow morning.
Robin van Persie has confirmed he will not attend the FIFA Ballon d'Or ceremony in Zurich because of the ankle injury he suffered in Manchester United's defeat to Southampton.
Van Persie's World Cup header against Spain is one of three goals shortlisted for the Puskas goal of the year award, which is due to be handed out at a lavish ceremony in Switzerland on Monday evening.
Manchester United has defeated Arsenal 1-0 at Old Trafford, with a header from Dutchman Robin van Persie sealing the match in the 27th minute.
Robin van Persie said there were "no hard feelings" after he completed a move from Arsenal to Premier League rivals Manchester United.
In his first press conference as a United player, he said: "From my side and Arsenal's side, there is no hard feelings. No one is angry with me and I'm not angry with them".
Manchester United have confirmed the signing of Robin van Persie from Premier League rivals Arsenal.
The Dutch striker has signed a four-year contract with Sir Alex Ferguson's side after eight years at the north London club.
Robin van Persie told the website: “It’s an honour to sign for Manchester United. I am looking forward to following in the footsteps of so many great strikers, bringing my experience and playing my part to help the team compete for the biggest trophies in the game. I can’t wait to get started.”
Sir Alex Ferguson added: “Robin is a world-class striker with a proven record in England and in European football.
"His talents need no introduction to our fans – he has scored a number of goals against us in some classic battles with his former club. His movement, finishing and all-round ability are outstanding.”
Arsenal football club say they are confident Robin van Persie will see out his contract at the club.
Arsenal said in a statement:
"We have to respect Robin's decision not to renew his contract. Robin has one year to run on his current contract and we are confident that he will fulfil his commitments to the Club.
"We are planning with ambition and confidence for next season with Arsenal's best interests in mind."
Arsenal striker Robin van Persie has announced that he will not sign an extension to his contract at the London club, which has a year left to run.
In a statement on his website, he said:
"I’ve thought long and hard about it, but I have decided not to extend my contract. You guys, the fans, have of course the right to disagree with my view and decision and I will always respect your opinions."
"My goal has been to win trophies with the team and to bring the club back to its glory days.
"Out of my huge respect for Mr. Wenger, the players and the fans I don’t want to go into any details, but unfortunately in this meeting it has again become clear to me that we in many aspects disagree on the way Arsenal FC should move forward."