De Zerbi took his Albion side to Rome to take on AS Roma in the Europa League last 16 first leg.
After a 4-0 loss, he stated: We lost against a stronger team than us.
It's not only a matter of statistics and systems.
Roma players are used to playing this kind of match.
I am Italian. I know these players, they were already good players.
Now they have become even stronger players but from a mental standpoint.
We are not used to playing games at this level.
We have achieved an historic result and now we are trying to hold on.
Today is the day I love the most my players. Not a single one played above 25% of his potential.
He added: It is an important lesson for all the club to learn from this game.
"For the president, because in the future we will be able to improve the team.
For myself, because maybe I will better handle the period from January to March, especially in England with such a busy schedule.
And for the players. Today they walk away with many regrets and, when you have regrets, you know what you can expect and you can improve and you want to do better.
We lost deservedly to a better team better also mentally."