Well since one day in this game equal one weak in real football, 24 hours means 7 days and 3 hours is 1\8 of the day (the weak) so it's definitely the same day. My point is you don't see CL matches on Saturdays and Sundays. You don't play in league and CL at the same day.
And when playing with 60% stamina or less it does increase injury ratio even that it is random, and more than that the players perform badly so you'd lose more often than not.