Having given his players a day off after their frustrating midweek goalless draw with West Ham, Jose Mourinho started work at Chelsea's Cobham training ground last Friday - dusting them down, then building them up.
But it was on Saturday and Sunday - two intensive, full-on 90-minute sessions, ending with Mourinho explaining the game-plan, albeit with the players expecting Oscar, rather than Willian, to start against City - that the seeds of Monday's triumph were grown.
Mourinho, pointing out City's weaknesses as well as their strengths, had said it all when he announced the team on Monday lunchtime, allowing masseur Billy McCulloch's dressing-room comedy act to ease the pre-match tension.
Gary Cahill: "He's got the CV for a reason.
"He's obviously a top quality manager.
"The club, obviously, is a massive club. And when you've got a massive club, with massive players, and you add a massive manager, it combines really well.
"It's not necessarily about egos, but he knows how to manage big players, and everything else that comes with it.
"We worked on a few things in the last couple of days, which he was adamant we would put into practice. And it did pay off for us.
"The plan was a secret, ha, so I don't want to say, just in case I get hammered for it! We had a strategy, and we worked on things, and they paid off.
"Just before we left the hotel, it came on the TV saying they hadn't failed to score [at the Etihad] since 2010. We were buzzing, hearing that literally 10 minutes before we set off!
"I think they were talking about how many it was going to be. But we defended really well. You have to work hard, don't you?
"They've got quality players, a lot of strength and power and sometimes they steamroller teams, out-muscles them.
"We needed to match that from the off and I thought we did. The work-rate was brilliant.
"The plan is nothing without the players, nothing at all."