Football, we are routinely reminded, is a results business so on that basis Manchester United should be in pretty rude health. Twelve wins from their past 14 matches in all competitions is a handsome return by anyone’s standards.

Results, alone, have never been quite enough to satisfy Sir Alex Ferguson, though. The United manager has always considered the level of performance as a means of more accurately gauging the form of his team, and whether he cares to admit it or not, the Scot may be a touch uneasy that, as the season enters November, the Barclays Premier League champions are showing few signs of improvement. United have usually found their stride by now, but with each game that passes, more questions are raised than answered, which is a troubling scenario.

Ferguson suggested that “you would never have guessed we are the league champions” watching the 2-0 defeat by Liverpool, but as disconcerting as that performance at Anfield was, United supporters might point to a series of laboured displays at home as a greater cause for concern.

Taken in isolation, the cumbersome 2-0 victory against an underwhelming Blackburn Rovers on Saturday was just that, but when United have previously made such heavy weather of modest teams such as Birmingham City, Sunderland and Bolton Wanderers at Old Trafford, and been fortunate to escape with victories against Arsenal and Manchester City, a pattern begins to emerge.

Blackburn are a distinctly average team, beaten 6-2 by Arsenal at the start of last month and trounced 5-0 by Chelsea at Stamford Bridge nine days ago, when even Sam Allardyce, their manager, branded them “pathetic”. United, though, are finding it alarmingly difficult to break down lesser teams, which hardly inspires confidence with an in-form Chelsea to visit on Sunday.

United have not scored more than two goals in a game since beating City 4-3 at Old Trafford on September 20, nine matches ago. In that time, they have scored 14 goals, three fewer than Chelsea have managed in their past four outings. Seldom do Ferguson’s players look capable of twisting the knife, as Arsenal and Chelsea are doing with regularity.

Dimitar Berbatov and Wayne Rooney scored against Blackburn, but the lack of thrust was startlingly evident. Blackburn urged United to attack them but the home team too often declined to take up the invitation. On the three occasions when dangerous balls were flung across the Blackburn six-yard box, there were no United players even close to getting on the end of them.

Aside from the obvious shortage of an attacking midfield player in the Frank Lampard or Steven Gerrard mould, it is noticeable that United lack a ruthless, aggressive streak and the final ball still needs a lot of work, even if that is to be expected with Nani, who moves closer to the exit door with every touch, patrolling one of the wings.

Gabriel Obertan looks a better bet than the Portuguese to succeed — which isn’t saying much — although the France Under-21 winger spurned the opportunity to make a name for himself on his league debut when he missed a sitter from six yards.

There were positives for United. In the absence of the injured Rio Ferdinand and Nemanja Vidic, both of whom face a race to be fit for Chelsea, Jonny Evans and Wes Brown equipped themselves well in central defence, even if Blackburn, for all Allardyce’s claims that Nikola Kalinic’s wrongly disallowed goal late on could have affected the outcome, offered little going forward.

And Berbatov and Rooney linked well on occasions, although their partnership remains very much a work in progress. Rooney’s goal, a delicious flicked finish from Anderson’s cross, would have been the highlight of most matches, but it was bettered by Berbatov’s sublime volley on the turn.

A performance against Chelsea would be nice, but on this form, Ferguson would gladly settle for a result.

Man Utd (4-4-2): E van der Sar 6 J O’Shea 6 W Brown 7 J Evans 7 P Evra 6 L A Valencia 6 M Carrick 7 Anderson 6 Nani 4 D Berbatov 7 W Rooney 6 Substitutes: G Obertan 4 (for Nani, 64min), M Owen (for Berbatov, 79). Not used: T Kuszczak, P Scholes, Fábio Da Silva, D Fletcher, R de Laet. Next: Chelsea (a).

Blackburn (4-1-4-1): P Robinson 7 P Chimbonda 5 C Samba 6 R Nelsen 5 G Givet 6 S Nzonzi 5 B Emerton 5 D Dunn 6 K Andrews 5 E-H Diouf 4 F Di Santo 4 Substitutes: M G Pedersen 5 (for Andrews, 57min), N Kalinic (for Di Santo, 76), B McCarthy (for Dunn, 83). Not used: J Brown, V Grella, D Hoilett, M Salgado. Next: Portsmouth (h).