Sometimes you wonder what would be left of our football - and Manchester United's link with the best of their past - if it wasn't for his ferocious drive to win every game he plays and with every scrap of his talent.
Such a moment came near the end of this game which was supposed to investigate the will of both Rooney's United and Liverpool to operate in the foothills of the Chelsea money mountain. Instead it was a sad statement about so much of Premiership football. It was a game without any kind of sustained edge, without any real belief in the value of true and natural aggression.
Yet with Rooney there are always possibilities. He ran around Xabi Alonso as though he didn't exist before sending a shot inches wide of a post. That was spontaneity, force, a surge of skill which could transform any contest, even one as dour and unadventurous as this one. Remarkably, it did exactly that - creating the momentum which saw Ryan Giggs' free-kick headed home by Rio Ferdinand in the 90th minute.
Earlier you might have been given 1,000-1against Rafa Benitez's iron curtain being breached as Rooney explored every last reserve of energy and ambition in an effort to animate United. It was then that you wondered about that limit on any assessment of Rooney. Was he the player of his generation - or the last of a species, an English performer operating with a genuinely inventive spirit and the technical accomplishment to support it.
The point was that for so long only Rooney's dash and bite invigorated the United effort, threatening Liverpool's apparently relentless ability to produce clean sheets. Ferdinand achieved the hero's status in the end, and Giggs ended with a flash of glory on a day when it seemed his career might be petering out along with his club's place as the most serious challenger to the march of Chelsea. Giggs sent in the beautifully flighted free-kick, Ferdinand struck and Old Trafford might just have believed the good days had come flooding back.
Certainly, United's veteran Gary Neville seemed to be suggesting that all was well when he inflamed the Liverpool fans with some triumphal clutching of his shirt, but another truth was buried in action which for most of the time can only have been of reassurance to Jose Mourinho.
The Chelsea manager may have regretted the loss of two points to Charlton earlier in the day, but here there was only the sound of extremely distant hoofbeats. Hence, the impact of Rooney's ceaseless running and flashes of invention. He refused to accept that Liverpool had come along to announce that his team had slipped down another rank in the pecking order of English football's aristocracy.
That, though, might well have been the reality but for United's late strike. The truth was that Liverpool for most of the time did look much the more coherent force. They covered the ground and generally looked the more confident side.
But again there was comfort for Mourinho. If Liverpool are the champions of Europe, if their powers of defensive concentration have become little short of awesome, they are still some way from a team ready to play with the confidence that comes with mastery of all departments of the game.
There is still a critical deficiency and it is in front of goal. Liverpool at times had enough control to win this game but whenever they moved in for the kill they were lacking in that crucial authority which sets apart the teams who know they are advancing to new levels of authority. First Peter Crouch, then Djbril Cissé could well have broken United, but the chances were missed and the old charge was raised again.
Benitez has made extraordinary progress at Anfield but he is still a long way from settling on a strike force of genuine conviction. Crouch brings craft and unexpected skills, Cissé has genuine speed, but between them they do not make the impact of natural-born winners. Indeed, the memory of men like Michael Owen and Robbie Fowler can only become more poignant as Liverpool work to make up that still vast tract of difficult terrain separating them from Chelsea.
They have to accept there is still quite a bit of climbing to do. The challenge at Old Trafford yesterday could not have been more clearly defined. It was to exert authority, to show that the time of waiting was drawing to a close. It just didn't happen. Liverpool were strong in defence and threatening at times when Steven Gerrard had some moments of fleeting impact. But United were allowed to hang on to the prize Sir Alex Ferguson so enigmatically says is of some value. He cannot really believe that second place is anything more than a briefest massage of the spirit.
One thing is certain. Rooney gives the idea no credence at all. He still plays like a man who believes he can beat the world, which of course still includes Chelsea. A Chelsea, that is, who have just learnt that they can probably afford more than an occasional slip.