Rooney's ability to partner other world-leading players - and to not only maintain his own excellence in doing so, but often to perform even better - is one of the qualities that makes him stand out even amongst other world class players. It's also surprisingly little-mentioned.
In every top team there is a regular issue with combining several of those 'best in the world'-bracket players without compromising any of them. Benzema has never quite been as consistently brilliant at Madrid as he might have had he not always played in Ronaldo's shadow. Ibrahimovic is just one of a number of players who Barca have never really got the best out of because of the importance of making Messi the focus of all their football. Throughout history, putting two of the best players in the world in one team has been hugely problematic. Making it work often leads that team to huge success, but struggling with it can also hamstring them for years.
Rooney, on the other hand, actively benefits from partnership with an equally brilliant player. It increasingly looks like it doesn't matter what sort of player they are, either - the requirement for understanding, sacrifice and codependance just seems to suit him.
He forged a stunning and prolific partnership with Van Nistelrooy. He was the foil to Ronaldo when he was the best player in the world. Now he and Van Persie look a good bet to retake the PL trophy for us. It's such a rare ability amongst top players to be able to gel with other top players regardless of their style and position, and it's hard to overstate how important that ability has been to the last eight years of United's success.