The Rondinelle have fallen into the Serie A relegation zone - four points from safety - after collecting just four points from their last eight Serie A games.
Their last victory dates back to December 12, when they beat Sampdoria 1-0, and the three defeats that followed have proved costly.
The 2-1 defeat to Cesena in their opening game of the year proved a hammer blow for Beretta's side.
They showed improvement in last Sunday's 3-2 loss at Fiorentina, but nevertheless slipped to second bottom in the standings and Beretta knows errors made against the Viola must not be repeated.
"The defeat at Fiorentina is a big blow," said Beretta. "Considering what my players did, we deserved the win but instead we go home empty-handed.
"We lost concentration in the last 10 minutes of the game and we were punished.
"This should be a lesson for my players that a match lasts for 90 minutes."
Beretta will be hoping his side raise their game this weekend, but knows that requires an improvement in defence with the team having conceded six goals in their last three games.
Parma travel to to the Stadio Mario Rigamonti hoping to put more distance between themselves and the drop zone.
The Ducale club started 2011 in the best possible way by beating Juventus 4-1 only to lose 2-1 to Cagliari in the last round.
"We continue to have ups and downs," said Parma captain Stefano Morrone. "We must prepare better for the games and concentrate on one game at a time.
"We need to get consistency in our results if we are to avoid a nervous end to the campaign."
Pasquale Marino's Parma head into the weekend 15th in the standings - four points clear of the bottom three.