's first-half tap-in was enough to allow Manchester United to begin the defence of their Barclays Premier League title with a 1-0 victory over Birmingham.
With Cristiano Ronaldo now at Real Madrid, Rooney has been restored to his preferred role just behind a main striker.
And the England man proved his well-being by climbing above Franck Queudrue to meet Nani's cross, then tapping home the rebound after his header had bounced back off a post.
Birmingham's response was spirited and after Cameron Jerome's shot had flicked off Paul Scholes, Gregory Vignal thought he had equalised from the corner, only for Patrice Evra to nod his header off the line.
It was a sporadic flurry of attacking play from the visitors, who were thankful not to be further behind at the break given Evra set up Darren Fletcher with a clear chance in stoppage time, only for the new Scotland skipper to steer his shot wide when it looked easier to score.
Some pundits wonder why Fabio Capello keeps faith in Ben Foster given the number of times he has been unavailable for England duty. In a split-second he provided the answer.
As Blues substitute Christian Benitez opened out his body out and went for the far corner, Foster flung himself in the same direction, flicking the ball away to let United breathe again.
Substitute Michael Owen did have the ball in the net once, only to be flagged offside. He was most certainly on when he raced onto Rooney's chested through ball in stoppage time.
But this time, Joe Hart made the save.