On their first appearance at Old Trafford since being thrashed 6-1 by Manchester City, Antonio Valencia's eighth-minute tap-in and a late deflected effort from Rooney ensured United grabbed maximum points from their clash with the Romanian outfit.
It was hardly a command performance, but in rampaging right-back Phil Jones and Rooney - who netted his 27th Champions League goal from a starting position in central midfield - the home fans at least had a couple of happy memories to take away from a stadium where the ghosts in blue will linger for so long.
As the inclusion of Rio Ferdinand in place of suspended skipper Nemanja Vidic had been confirmed in advance by Ferguson, it was Rooney's starting position in midfield that attracted most attention.
It is an area of the field Ferguson has been urged to strengthen for two years and, in the wake of that "embarrassing" City "debacle" as Ferguson described it in his programme notes, those calls have reached a crescendo.
Whether there is a concrete idea formulating in Ferguson's mind remains to be seen.
However, there was clearly an intention to give Rooney a full opportunity to express his talents given Javier Hernandez was introduced when Michael Owen limped sadly down the tunnel after 11 minutes, the victim of yet another muscular injury.
By that stage United had already got their noses in front, with Rooney playing a significant role with the pass that released Dimitar Berbatov.
The Bulgarian released Jones on his outside, the full-back eventually cutting a cross back that bounced past Owen's near-post lunge and left Valencia with a tap-in.
It should have been the start of a goal avalanche against limited Romanian opponents, but United lost their way somewhat.
On a couple of occasions Berbatov was left frustrated as Hernandez stormed into the box but nudged the ball slightly too far in front.
Fabio embarked on an eye-catching burst from halfway, only to run out of room as another opportunity petered out meekly.
Without a point in Group C, Otelul showed limited ambition.
However, when a stray Nani pass rolled to Ionut Neagu, the young midfielder went for goal before Ferdinand could close in and brought an excellent one-handed save out of a previously underemployed David de Gea.
With Rooney operating as a virtual quarterback, sitting just in front of the back four and directing operations with a decent variation of passes, Hernandez and Berbatov attempted to gel.
Berbatov showed a nifty turn of pace to latch onto Hernandez's eye-of-the-needle through ball, but was unable to beat Branko Grahovac from an acute angle.
Hernandez could not beat the goalkeeper either with a shot on the turn after collecting Rooney's forward pass.
Soon afterwards, Berbatov blazed a shot over from Anderson's lay-off before the pair exchanged short passes, only for the Brazilian's goalbound effort to be booted clear by Sergiu Costin.
Rooney was next to try his luck with a curling effort from the edge of the box that failed to trouble Grahovac.
Yet that failure, in addition to the growing nerves at a succession of Otelul attacks that brought no reward, merely highlighted the problem of Rooney's use in midfield.
Sure he can adapt, as most top-class players would. His pass completion rate was of the level the watching Paul Scholes would be proud. One pass to Berbatov with the outside of his right foot was simply sensational.
But his absence from the forward line costs United plenty in terms of an attacking threat, even allowing for the abilities of those asked to do the job instead.
Jones's claim on the man-of-the-match prize strengthened with another probing right-wing raid that ended with Hernandez glancing a header over, then Berbatov turned away in anger as Nani ignored him and tried to beat Grahovac with an ambitious curling effort.
Not that Berbatov had anyone to blame but himself as he strode beyond the visitors' defence but blazed his shot into the side netting.
Adrian Salageanu's dangerous free-kick that bounced past half a dozen advancing team-mates and through to De Gea was further proof of United's perilous position.
Rooney ended the anxiety with a long-range effort that took a massive deflection off Sarghi three minutes from time.