My leaderboard has all but three teams active so unfortunately I do have to concentrate on winning otherwise I would lose the lead (I would love to be in a position to not have to worry or to set and forget because the challenge is quite repetitive and boring). I have noticed I don't think it's formation that makes such a difference but moreso the orders. I think it's important (in this challenge) to be quite offensive... attacking mentality, plenty of up arrows, man to man, hard press if cannot score in first 30 minutes, no short passing until you have the lead, etc. Of course, I do change formation to try and counter Mourinho's formation each game as well but I find being attacking is the most important factor.