The Bianconeri lost 2-0 at Atalanta last weekend, their third defeat on the road this season.
Udinese, who remain unbeaten at home, have won just one of their last four games and lie 12th in the standings.
"Atalanta deserved the win," Guidolin said. "They were hungry and determined.
"We were terrible in the first half and made far too many mistakes. I'm not happy with how we are playing and with my players' attitude.
"We need to start recovering that winning mentality that we had last season and for that to happen, we need to get good results.
"My players need to start playing like Atalanta did, with a knife in between their teeth."
Cagliari coach Diego Lopez, meanwhile, focused on the positives after his team snatched a point in a 1-1 draw against Inter Milan last time out.
The result lifted the Sardinian club to 11th place, level on seven points with Udinese.
"We held out well against a great team like Inter is," Lopez said. "Every now and then we disappear from the game, so we have got to find consistency."
Cagliari have reason to be confident heading into this weekend's game in Udine for they have lost just once this term, a 3-1 defeat at AC Milan.
Lopez will be missing injured midfielders Albin Ekdal and Andrea Cossu while midfielder Daniele Conti must serve a one-match ban.
Udinese captain Antonio Di Natale will lead the Bianconeri's attack with Luis Muriel still sidelined through injury.