The Friuli outfit visit promoted-side Sassuolo on Wednesday evening looking to bounce back immediately from their 1-0 reverse to Roma.
Udinese were holding 10-man Roma to a goalless draw only to concede a Michael Bradley goal eight minutes from time.
The result was Udinese's third defeat in four games and saw the Bianconeri drop to 11th place.
"We gave everything against Roma," Guidolin said. "We deserved so much more and I think Roma were fortunate.
"The only thing we lacked against Roma was the finishing touch and a little bit of luck.
"We have to forget this defeat immediately and try to show the same motivation in our upcoming games. We have to be more clinical.
"On Wednesday we face a big test and we cannot fail."
Udinese have lost all four games on the road this season but hope to stop the rot at the Citta del Tricolore stadium.
However, the Bianconeri will come up against an improved Sassuolo, who followed their 2-1 win over Bologna with a goalless result at Catania last time out.
Sassuolo coach Eusebio Di Francesco had reason to be satisfied as his side kept a clean sheet for the first time this season.
"We made some adjustments in our formation and we were able to find more balance," he said. "We took a small step forward in Catania.
"One positive sign is that we didn't concede a goal and this shows that the work we are doing in training is paying off."
Sassuolo still have the leakiest defence in the competition alongside Bologna, with 22 goals conceded.
Thankfully, they take on an Udinese side that have found the back of the net just twice on their travels.
Guidolin could rest veteran striker Antonio Di Natale in view of Sunday's game against Inter Milan and hand Reginaldo Maicosuel a start alongside Luis Muriel in Udinese's attack.