Manchester Utd - 2 Birmingham - 0: There are times when the Premiership's razzmatazz is scraped away and the competition is exposed as the most lopsided of contests. The best league in the world? Occasionally perhaps. Mostly, however, the imbalance of talent is such that Birmingham City, like Charlton Athletic, Southampton and Manchester City before them, can come to Old Trafford and not even muster a shot on target.

If this truly is a better league than Serie A or La Liga we would surely not be in a position where Manchester United, not even the first-placed club, have conceded only three league goals at home in four months. Steve Bruce and his Birmingham players were just the latest to contribute to another weekend of relentless, week-in week-out superiority and it said it all that they could even congratulate themselves on a good day's work.

Manchester United's fans probably could not care less that the gulf between the best and the rest is becoming so cavernous and the men in power at Old Trafford cannot be too concerned given that work will soon begin to extend the stadium's capacity from 68,000 to 75,000. This is a club, after all, that could attract more supporters to a book-signing session than others get for a league game. Yet Alex Ferguson has used the word "mundane" about the league programme and this was one of those afternoons when it was difficult to gauge any sense of genuine pleasure among England's biggest and most blase crowd.

Ferguson's men certainly seem determined to prolong the argument with Chelsea but this did not feel as though we were watching a team going for the championship. Whereas every match at Stamford Bridge is accompanied by a frisson of nervous excitement, Old Trafford has become a place of conservatism for games against fair to middling clubs such as Birmingham, as if the supporters are unconvinced by Ferguson's argument that Chelsea can still implode.

Granted, there were glimpses of excellence from Cristiano Ronaldo and Wayne Rooney, and most notably there was the endearing longevity of Roy Keane, whom even the most casual observer must have noted was the man who mattered.

Much has been made of Keane's 55th-minute goal being the 50th of his United career but the most important aspect was the restorative effects it had on the team just as it had seemed they were losing their way. Bruce spoke afterwards about the possibility of his former colleague going into management. "Believe me, there will be plenty of takers," he volunteered.

On this form, however, Keane should be concentrating on extending his playing life. It was easy to lose count of how many times he made telling interceptions and his goal, collecting Ronaldo's clever backheel and driving forward before firing into the bottom corner, was a classic of determination and willpower.

An air of inevitability had descended long before Maik Taylor shunted Kenny Cunningham's weak back-pass straight at Rooney who lifted the ball over the goalkeeper to make it 2-0.

This was a lacklustre, strangely subdued United performance but, most of the time in the modern-day Premiership, that is enough to see them through anyway.