They will have spent the last two months thinking about and planning for this one game against Real Madrid tonight. But Manchester City need to find a new mentality, particularly in defence, if they are to get past Real and go on to win the Champions League.
City are on the tough side of the draw and they'll need to beat someone like Juventus, Bayern Munich or Barcelona to even get to the final.
It's the hardest route in the tournament. City at their peak would have the beating of Barca, but Bayern have looked very strong since they went back playing post-lockdown so they'd be a hard side to beat.
City have as good a chance as anyone in the tournament to win it, the squad is strong, although Sergio Aguero missing tonight's clash is a big loss.
Get past Real Madrid and they'll be a hard side to beat in the rest of competition.
But they need to be sharp and the old concern with City is the defence, as always.
They lost nine Premier League games and a lot of those defeats were down to individual errors, and cutting them out for a run of games against Real Madrid, maybe Juventus and Bayern Munich or Barcelona is not easy to do.
Every team has its weakness and this City side is no exception.
They can dominate games but make mistakes: look back at the Southampton match last month, they had 20 shots on goal, but conceded a sloppy goal themselves by giving the ball away in midfield.
Southampton punished them that day and at this level, facing Real Madrid in the Champions League last 16, you'll definitely get punished. So they need to adopt a mindset where, no matter how much they have dominated the ball up to then, the change from attack to defence has to be quicker.
That's a mindset where every player makes himself difficult to get past, difficult to beat.
City need that right across the team if they are to beat Real.
Because Real are 2-1 down from the first leg, they've nothing to hold on to, so they can come out and play with freedom, try to exploit City's weaknesses.
So the job for Pep Guardiola over the last two months, and in the build-up today, will be to focus on those mistakes and cutting them out.
I think the message in training to the City players this week will have been to not be afraid of just clearing the ball if there is a danger, you don't always have to try and play the clever ball out of defence.
In the first leg - and that was played a long time ago, back in February - Guardiola went with a plan which confused everyone and then changed it with 20 minutes to go ... and it worked as they scored twice. They took Real by surprise, how they started the game and then how they finished it.
Now Pep needs to have his tactics in place, but also tell his players to be wary of what can go wrong.
To me, the first game played in the tournament after the restart will be key to winning the trophy. It's not just winning through a round but playing so well that you draw confidence from it.
Someone like Gabriel Jesus hasn't played that well since the season resumed, but if he scores one in the first match back, against Real, that could be the spark he needs to score five in three games and maybe push City on to win the Champions League.
So momentum is vital when the tournament has such an unusual fixture list.
But Real tonight is a very tough match for City. They are favourites as they won the first leg, but Real have been strong since they came back playing.
City had two big wins in their last two Premier League games, but beating Watford 4-0 and Norwich 5-0 is not really an indication that you can then go and beat Real Madrid.
More relevant to tonight's game is what has happened behind the scenes, how they have worked on the intensity needed and how they will have the pitch just right for this game tonight.
Everything City have done for the last two months was about being ready to play Real.
City can be so good on their day that the opposition can't handle them, as Watford and Norwich found out, but it's also about keeping up your intensity in training.
When City played Arsenal in the FA Cup the manager said they weren't quite there yet, I took that to mean they had known the league was gone but they were building up for two months to have them at their peak for the Champions League.
City have tried a couple of things in the last few games, used different partnerships in defence and given most of their squad a run to build up that tempo.
All the focus has been on August and the Champions League.
A team like Bayern Munich have had a few weeks more than City since their last competitive game and could struggle to get their rhythm up to the required level.
We've seen this before with the likes of PSG: when they get to the knockout stages of the Champions League they've already won the domestic league so the intensity, the competitive edge, has dropped.
Apart from Gareth Bale being left out, the Real squad seems to be a reasonably happy place at the moment, although they will miss Sergio Ramos, as he is a real leader.
But they have so much quality in their squad that you know they will attack.
In Zinedine Zidane, Real have a manager who knows how to get over the line in the Champions League and that's one of the things that makes them a threat.
I can see City beating Real Madrid, they have enough quality to win the tie, and if they can cut out those individual errors there's no reason why they can't go on and be crowned Champions League winners.