Finally appearing as a 60th minute substitute for Ole Gunnar Solskjaer at Fratton Park, Rooney single-handedly snared three points with two goals in the final 13 minutes, followed by the final goal in Wednesday’s win over Watford.

Ferguson has extra options up front for tomorrow’s difficult trip to Tottenham following the return of Louis Saha from a knee injury. But Rooney in his current form is certain to be the first name on his team-sheet.

Ferguson said: “I think he has taken encouragement from getting a rest. We left him out for the Pompey game and I think that was worth doing from his perspective because it gave him the opportunity to realise how important it is for us.

“Even just an hour’s rest seemed to galvanise him. He came on as a fresh player almost, and I think that was important for us. These odd goals he is scoring give me great encouragement that he is coming into his best form now.”

Such is Rooney’s superb goalscoring record there was talk of a mini-crisis earlier this season when he went eight games without scoring before responding to his drought in typical fashion by netting a hat-trick at Bolton.

And Ferguson is now convinced that Rooney’s work ethic and continued willingness to learn has helped him emerge from another relatively barren spell in recent weeks to play a significant role in the destiny of the Premiership title.

Ferguson added: “If he can get to that one goal per game thing then the odd goals and deciding goals make all the difference to our season. We haven’t had that off him but if it comes it definitely gives us a massive chance.

“He is not a goalscorer who is going to stay in the penalty box. He wants to link the play and be in the box at the same time and because he is 21 he has not got the knowledge to do both things.

“The part we want to see the development in is where he starts getting these odd goals. It will make a hell of a difference to him as a goalscorer because he is a finisher, there is no doubt about that.”

Rooney should be partnered by Saha in attack at White Hart Lane, with Solskjaer the man to make way in squad which is reaping the benefits of such fierce competition for places at a crucial stage of the season.

Trips to the likes of Chelsea, Liverpool and Manchester City still remain this season and Ferguson will not under-estimate the challenge posed by Spurs counterpart Martin Jol, of whom he is a great admirer.

But having performed the master-stroke of bringing in inspirational Swedish veteran Henrik Larsson on a short-term loan, Ferguson has ensured that the mood within Old Trafford could hardly be better at this stage of the season.

O’Shea’s starting chances have been kept to a minimum this season but even the Irishman admits that is a small price to pay for the prospect of adding to his collection of Premiership winner’s medals.

O’Shea said: “It is obviously frustrating when you are not playing week in, week out but that is the case when everyone is fit and you are top of the league. The manager has big decisions to make and when you get your chance you have got to take it.

“Everyone is chomping at the bit to get into the team. In the last couple of seasons we have had vital players missing for months but this season we have coped with everything that has been thrown at us and you can see we are enjoying it.”