When Manchester City travelled to the Camp Nou two weeks ago, the biggest surprise wasn’t the scoreline, nor even how well City played despite losing 4-0. The biggest surprise of the night was the fact that whilst playing at the home of arguably the best football team ever assembled, Pep Guardiola left out of his starting lineup arguably the best striker outside of Catalonia.

Though it was also genuinely surprising how well City played. Guardiola took the decision to leave out his striker because, he reasoned, City would be more effective in stopping Barcelona from playing if he had an extra midfielder.

The best way to stop Lionel Messi, Luis Suarez and Neymar is by depriving them of the ball. And you do that either by keeping hold of it yourself, or by stopping Sergio Busquets from giving it to them. It’s a reasonable plan, and one that almost worked, strangely enough given the eventual scoreline.

The truth is that City were actually the better side until Claudio Bravo was sent off. The game plan worked, City stopped that stellar front three from dominating the game, and it was a slip from Fernandinho that eventually granted Messi his first half goal.

It’s easy to spot attacking flair, but difficult to pinpoint good defending - certainly in real time during the game. You have to actually study a passage of play to understand the defensive mechanisms involved, but you don’t really have to study an attack to see its merits - not to the same extent. Football is made up of its macro, visible parts, and its micro, invisible-to-the-naked-eye parts. And the fact that City’s pressing and shape at the Camp Nou prevented Barcelona from getting a foothold in the game in the first half falls very much into the micro level.

So much so that at half time, BT Sport's pundits lamented a game of poor quality. Poor attacking quality, that is. Visible quality. But if you dissect it and put it under the microscope, you’ll find a different state of affairs. A game lacking in attacking flair was, perhaps, just the consequence of City’s game plan.

The problem is, one of the other consequences was their toothlessness in front of goal.

There were times when Guardiola’s side cut the Catalans open. There were times when Raheem Sterling broke into the box, and times when Kevin de Bruyne's clever runs into the channels saw him break in behind and get to the byline. But all of those times, there was no City player in the box to get on the end of a cross or a cutback.

The tragedy of City’s plan to stifle Barcelona was how well it actually worked. It worked so well that City saw quite a bit of the ball themselves, as the Catalans’ passes went awry. It worked so well they were able to create chances against a team who usually only give them up on a lucky counter attack. But because it went so well, Guardiola had no striker to find the right space in the box for the sorts of cutback opportunities City were creating: there was no one there to actually score the goal.

Playing against Barcelona is all about how brave you want to be. Tactically, it’s probably easier to play against them than it is to play against anyone else: you know exactly what they’re going to do. They’re just almost impossible to stop. The game plan, then, is either sit back and deny them spaces and gaps to work in, or it is to come out of your shell, press them with intelligence and try to actually battle them for possession of the ball.

And for City tonight, it’ll be a similar trade off. How brave will Pep Guardiola be? Will he feel chastened by the 4-0 scoreline, or will he look at the positives in how his team played until the red card? Will he decide that his pressing game without a striker was good enough to justify leaving Aguero on the bench again, or were his team good enough to create chances that he simply needs a striker this time?

For the first time, it might just be that City feel good enough to take the game to Barcelona and feel on a level footing.