It looked pretty nasty but we're not sure that it will have done any damage to his noggin.
You always need to show you'll do anything for the cause for your football team, especially if you're the captain. And you definitely need to do that if you're playing in one of the biggest derbies in the world, like say, the Manchester derby.
Whether it be a huge tackle, taking a booking for your team or putting your head where you know you'll probably end up getting kicked or hit.
When the two captains clashed, Rooney managed to come off worse and was left with a ponytail of blood streaming from his head and putting us right off our Sunday lunch - though when doesn't he?
With Rooney's head streaming, Twitter definitely had a field-day and here are some of the best tweets regarding Rooney's cut... look away now if you're not good with blood...
As for the game itself, Rooney's injury was probably the most eventful part of it. A dull 0-0 draw which had nothing on the Wear-Tyne derby...
Wayne Rooney's Blood Bath sounds like a straight to DVD film directed by Jean-Claude Van Damme pic.twitter.com/otnF71OUMu— Top Corner (@HITCtopcorner) October 25, 2015
Not sure about Rooney's latest hair transplant... pic.twitter.com/IVqC2SbGZP— JOE.co.uk (@JOE_co_uk) October 25, 2015
Wayne Rooney's got blood gushing from a head wound. Perhaps the weave's coming loose?— Dream Team (@dreamteamfc) October 25, 2015
Wayne Rooney with a white trash blood rat tail— Kessler for Hire (@scottdkessler) October 25, 2015