Another example, in my team in OMA league yesterday.
I couldn't watch the game and I lost from the last team of the league. Later in Champions League, with the same starting 11 and the same formation, I won 13-1, but I was there.
So, for me it's no the answer.
If the question was " Does the presence of the manager secure that the team will perform always better ?" then I 'll agree that the answer is also no.