By Jonathan Wilson
When Manchester City met Manchester United at the end of April last year, in a game that seemed - and turned out to be - effectively a play-off for the league title, the game was settled by a single goal, a header powered in by Vincent Kompany from a right-wing corner. 1-0, though, didn't really sum up how dominant City had been.
Physically, they had bullied United in midfield; that was where the game was won - and it was won convincingly. What is strange, though, is that having had such an obvious advantage in that regard, City have changed approach.
In part, that was down to the midfield United employed. Michael Carrick, Paul Scholes and Park Ji-Sung, who was making his return after several weeks out with injury and so lacked his usual energy, formed a trio of neat, technically adept but not particularly imposing thirtysomethings. Ryan Giggs and Nani, dropping back form wide positions, didn't really help. Wayne Rooney was used as a lone striker and so couldn't drop deep enough to add his ball-winning capabilities and muscle.
City, meanwhile, had Gareth Barry sitting implacably in front of the back four with Yaya Toure alongside him, charging up and down, imposing himself with his combination of power and finesse. Sir Alex Ferguson's hope, presumably, was that playing an extra man in central midfield would be sufficient to counter the added bulk of City's pair, but with Carlos Tevez dropping deep off Sergio Aguero - doing what Rooney could have done had he played off a front man - and Samir Nasri and David Silva playing quite narrow, City controlled the midfield. The introduction of Nigel De Jong for Tevez midway through the second half only confirmed City's superiority in that area.
De Jong, though, has gone, sold to AC Milan. Barry plods on, unspectacularly efficient as ever, but Toure has looked out of sorts this season. In form, he is a phenomenon, blessed with extraordinary stamina and strength, but also a fine technical player with both great drive and intelligence. He hasn't been awful this season, far from it, and at times he has dragged City forward, but like most of the side, he is not quite in top form.
City will, though, presumably employ the same 4-2-3-1 they did in April. They have often used that same front six this season - although there is the possibility Edin Dzeko could start - but the shape has been far more of a 4-4-2; given how well the shape worked then, there seems little reason to change.
Then again, there seemed little reason to change anything at City last year; with by far the best squad, they were by far the best side. Roberto Mancini, though, seems determined to shift to a game based more on possession than power, an experiment of which it's perhaps kindest to say that it's still in its transitional phase.
De Jong's departure is perhaps the most obvious manifestation of the change of approach, but Mancini has also broken up the centre-back pairing of Kompany and Joleon Lescott, seemingly because Matija Nastasic is better in possession. The dabbles with a back three, similarly, seem an attempt to hold the ball better.
To an extent it's working; City's possession has gone up from 58.2% per game to 59.3% and their pass completion rate from 85.9% to 86.4%. But there has been a cost - Kompany, a superb defender and an eloquent leader, has not been at his best.
From set plays in particular, City look vulnerable - which is of particular concern given that United have already scored 10 times from set pieces in the league this season, more than any other side.
City may still be unbeaten in the league, but much of that has been down to individuals suddenly producing moments of great quality rather than any great coherence of team play, something that, along with the defensive shortcomings, has been exposed in the Champions League.
And this is a different United that City will face, if only because the presence in the squad of Robin van Persie allows Rooney to play deeper so he can go back into midfield and forage for the ball if required. With Tom Cleverley suffering a calf injury, it may be that United are forced again to play Scholes and Carrick at the back of midfield but at least they have his aggression and energy unsettling Barry and preventing him setting City's tempo.
Yet United, of course, have been just as unconvincing as City. They've gone behind an astonishing 14 times this season and, while comebacks were a thrilling feature of the treble in 1998-99, the concession of early goals is hardly an advisable policy; even that side were eventually caught up by the habit in the 3-2 home defeat (after a goalless draw in the first leg) to Real Madrid in the Champions League quarter-final.
Ferguson has described United's defending this season as being a "cartoon cavalcade" (apparently a reference to Sunday afternoon Scottish television from many years ago) as they continue to miss the calming solidity of Nemanja Vidic and neither David De Gea nor Anders Lindegaard convinces enough to secure the goalkeeper's shirt on a permanent basis.
And that's what makes this derby so fascinating.
United are three points clear at the top of the table (although City are three points better off than United in comparison with equivalent fixtures from last season), and there is a seven-point gap from City to Chelsea in third, but neither team has really convinced this season. Either could suddenly click into a run that effectively has the title won by March, or both could falter and fall back into the back.
These are two teams fumbling around for form, not far from it, and still better than most of the sides around them, but neither are firing yet.