Similar thing happened to my daughter around the same age. But the forthcoming Saturday game makes it extra awkward. Do you know the other girl’s mother well enough to ask her if her daughter wants to go after leaving your daughter off her party invite list? Explain your daughter is upset, you know what they are like at this age etc. If not, perhaps grit your teeth, take the girl and see how it goes. If there is clearly still a problem you just have to let it go and talk to your daughter about other friends. Very tough though. Girls can be so casually cruel and tend to have ‘best friends’ more than boys.