The striker, who has spent a month on the sidelines after a serious gash to his thigh, explained on Twitter that he had been remembering Stephen Johnson, a cystic fibrosis sufferer who died at the age of 24.
Rooney, 26, tweeted: “I wore black armband for my friend ste who sadly passed away last week. It was his funeral today. R.I.P. Ste.”
Wife Colleen also added her sympathy, saying: “He was a good friend of ours, especially my mum! So sad. Fantastic turn out for our mate Ste!! Lovely service, you’re going to be missed by so many! Goodnight Godbless x”
United won the game 2-1, with Rooney playing 76 minutes at Old Trafford.