The Biaonconeri have experienced their first Champions League campaign this season.
Guidolin said: "I think there is still petrol in the tank, as we do have physical fitness and athletic tests are positive. Determination and concentration are crucial to beat the big clubs. We must also remember that Udinese have never fought for Champions League qualification for two years in a row, so that must fill us with pride.
"At the start of the season we were the side everyone said was at risk of relegation, having started early with the preliminary round against Arsenal. I don't know about you, but I feel great pride, motivation and enthusiasm looking back at the last two years.
"I don't know if we'll qualify for Europe again, but with 20 days left to the end of the battle, we are still up there."