Lower rated clubs beat higher rated clubs all the time in real life, and I'd expect the same thing to happen in T11. The game probably has an element of randomisation built into it to allow for how unpredictable football is; if the best team won every them then i'd have won a mint on accumulators by now!

Take a few things into account: Is their player quality average lower cause they've got some low rated players they haven't shifted? Does the team have a massive win bonus that your team doesn't? Was their team better rested and with higher morale? Were your subs effective?

Not unusual