Birmingham City 0 Manchester United 1: Ronaldo picks up the slack for ominous United

It is more 1980s Liverpool – or, in terms of results, Arsenal under George Graham – and it probably would not measure up for Roman Abramovich in terms of winning with style.

But, having taken eight matches and seven weeks to manage what Portsmouth achieved in 90 mad minutes at Fratton Park on Saturday, Manchester United are bearing a certain ominous look early in their title defence.

Unfamiliar as the "1-0 to the United" chant is, momentum is steadily growing in a manner that must make their rivals wonder what will happen when the shackles do come off.

There was little fluency or conviction about a performance that extended the season's most freakish statistic to only seven Premier League goals scored by the end of September, compared with 17 rattled in at this juncture 12 months ago. Just about good enough to reclaim the second spot prised away from them for a few hours, it was nevertheless a labouring effort that allowed Steve Bruce genuine hope of overseeing Birmingham City's first victory over his former club for 29 years.

While Sir Alex Ferguson waits for his colossally talented forwards to fire, he is taking satisfaction at the way the dirty work is being attended to at the other end. United had countless scares in the first half of this rousing contest – one the manager called the hardest his side have faced this season – but the last-ditch defending, often to retrieve self-inflicted damage, was outstanding.

Edwin Van der Sar's fine saves from Cameron Jerome and Franck Queudrue in the opening two minutes followed uncharacteristic Paul Scholes doziness and then loose marking at Sebastian Larsson's corner while Rio Ferdinand chested Gary McSheffrey's header off the line after Patrice Evra's ghastly error and Nemanja Vidic tidied up when the keeper miscued a clearance to Jerome with his net gaping.

"There's no better feeling than coming off the pitch when we've won, especially with a clean sheet," said Ferdinand, speaking like a true defender. "The longer we do that, the better chance we have of winning things.

"We don't want to make a lot of winning 1-0 and being near the top. We are still not playing free-flowing football as consistently as we would like but it is gradually getting there and, if we can keep adding to what we are doing and keep clean sheets, we've got the players who can unlock any defence. Ronaldo's movement was the best I've seen for a long time."

On the day John Terry gave England another injury scare, his international partner was magnificent. He even helped make Cristiano Ronaldo's winner, although Queudrue's horrible defending on the edge of the area was the main "assist". Tomasz Kuszczak, on at half-time because Van der Sar suffered a toe injury that makes him doubtful for the Champions League home game against Roma tomorrow, then preserved the lead with a wonderful reflex save when McSheffrey's shot deflected off Ferdinand's head.

Less encouraging for England was Wayne Rooney's contribution. He and Carlos Tevez are among those not yet in to their stride, overshadowed here by Ronaldo in his 100th Premier League start.

The Portuguese forward's finish was assured, albeit gift-wrapped; a dash of extra quality during a testing tea-time in which an earlier breakthrough at the other end would have made this even more interesting viewing.

As much as Birmingham remain preoccupied with survival, they took a point at Anfield the previous weekend and deserved one here. There is considerable hope for them if they can maintain anything like this intensity at St Andrew's, where their defending was up to scratch for long spells.

As for United, five League victories without conceding a goal have to count for something. The fireworks will come later.

Goal: Ronaldo (51) 0-1.

Birmingham City (4-4-2): Taylor; Kelly, Djourou (Schmitz, 75), Ridgewell, Queudrue; Larsson, Muamba (Palacios, 70), Nafti (O'Connor, 84), McSheffrey; Jerome, Kapo. Substitutes not used: Kingson (gk), Danns.

Manchester United (4-4-2): Van der Sar (Kuszczak, h-t); Brown, Ferdinand, Vidic, Evra; Ronaldo, Scholes, Carrick, Giggs (Saha, 63); Rooney, Tevez (O'Shea, 88). Substitutes not used: Anderson, Pique.

Referee: S Bennett (Kent).

Booked: Birmingham City Queudrue, Nafti, Larsson; Manchester United Evra.

Man of the match: Rio Ferdinand.

Attendance: 26,526.