The Dutch striker congratulated the Manchester City Under-9s team - his son plays for them - saying he was "very proud" of the lads. The tweet contained a photo which showed him celebrating with the team of budding City starlets.
This riled some Manchester United fans, who felt Van Persie was wrong to celebrate a City win, regardless of whether the players in question are still in primary school. The same fans were then angered even further after Van Persie published a photo with Chelsea's Under-9 side less than an hour later.
It must be noted, however, that the majority of Twitter users - Manchester United fans included - saw nothing wrong with Van Persie's tweets and took it upon themselves to tell the rest to calm down.
Van Persie, meanwhile, appeared pretty non-plussed by the comments and opted against replying to any of them.
Van Persie watched alongside Fletcher
The former Arsenal captain, who could leave Old Trafford this summer following a second consecutive frustrating campaign, watched the action back in his native Holland alongside his former Manchester United teammate Darren Fletcher.
Fletcher's son also plays for the Manchester City's youth team, as does the son of Class of '92 member Phil Neville.
Shaqueel van Persie is apparently a very talented young player. He showcased his skills in a recent video posted online by his dad, which showed him scoring a sensational scorpion-kick goal in his back garden.
Why aren't the kids with United?
It still seems a little strange that the children of Van Persie, Fletcher and Neville are learning their trade in the youth team of Manchester City rather than Manchester United.
Whether United felt they weren't quite talented enough is unclear, but it's unusual that three big stars would all choose to send their children to the same club - and a rival club, at that.
It suggests Manchester City's youth set-up is now amongst the best in England; ft's no secret the Citizens have invested a significant amount of money improving all aspects of the club over the past few years.
Were Manchester United fans right to feel angry with Robin van Persie over these two tweets? Have your say in the comments section below!