The Udine-based club have finished in the top five in Serie A in the past three seasons but have started the new campaign with just four victories in 11 matches, including three losses in their past four games.
Guidolin remains convinced Udinese are a competitive outfit, however, and wants them to remain positive for their trip to Sicily to play Catania.
"We can't seem to transfer on to the pitch what we do during training sessions," the 58-year-old said on Friday.
"I hope this week, which has been intense and anxious, has made everybody aware of the situation we are facing.
"We don't have to be too pessimistic, this is just sport and tough moments happen also to bigger teams than ours.
"But I expect a positive reaction from my squad tomorrow."
The frustration against Udinese seemed to reach breaking point last week as they lost 3-0 at home to visiting Inter, while Guidolin's team face Fiorentina, Juventus and Napoli after their trip to Catania.
"The defeat to Inter has been negative for our image," Guidolin said.
"We didn't play well and we conceded two goals from set-pieces – we can do better than that."
Guidolin will have to do without captain Antonio Di Natale on Saturday as the veteran striker struggles with a knee injury, while Maicosuel will also miss the match after picking up a knock.
