Former Arsenal chief scout Comolli, now Tottenham's sporting director, revealed Wenger used to be physically sick following a poor result.
"You shouldn't be in this job unless it really hurts you to lose a game. If it does not hurt, then you will never survive in management.
"I admit I am never in good health after losing and my emotions are linked with my health.
"Sometimes there are periods when I can hide those emotions quite well. Other times less well.
"Somebody said that every victory slides over you and every defeat stays with you. I agree.
"I always feel terrible when I lose games because every defeat at this club is a crisis.
"No matter what you have achieved in the past, you always feel you could have done more."
It is that attitude which makes Wenger so impatient with people who do not fulfil their potential.
He said: "I do not respect people for their talent but for how they get the maximum out of it. Anyone can have talent with the right genes but what you do with it is down to the individual. I have met many players with as much talent as Dennis Bergkamp or Thierry Henry who never achieved anything at all."