But Ospreys produced an impressive six-try showing to down the Italian outfit 36-3 in the last game before the clubs head into European action.
Zebre's first Challenge Cup match is a trip to face last year's winners Gloucester and after not approaching the Ospreys fixture with the right mindset, Guidi is keen to correct that.
"When the team has the wrong attitude and does not play with humility then they suffer the sort of defeat we did against Opsreys," Guidi told Zebre's official website.
"Our goal is building a mentality that we can challenge everyone, so I am angry. But I think for the construction of our team, given the attitude we showed, we can learn from having to taste such a heavy defeat.
"You cannot give away possession to a quality team like the Ospreys, who did not wait to spread the ball and put pressure on us.
"We must all do some soul-searching and find our fighting attitude and the desire to play using our strengths.
"Against Ospreys we did not play as the Zebre of the last few matches - there are always some errors when trying to build a team but the initial attitude is not acceptable at this level."
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