Guidolin, whose side are unbeaten after seven games and visit erratic Napoli on Wednesday, wrote off Udinese's title chances after their 3-0 home win over Novara on Sunday sent them to the summit.
"We can't fight for the scudetto," Guidolin, whose side have 15 points and are the only unbeaten team in Serie A alongside Juventus, told reporters.
"None of the other coaches have mentioned Udinese among the possible title winners and I trust my colleagues, they understand football.
"In the dressing room, we have a notice with our aim, which is to reach the 40 points needed to avoid relegation, so we are still 25 short.
"We will enjoy it for one day but we have no reason to get carried away."
However, with striker Antonio Di Natale, last season's league top scorer with 28, still knocking in the goals they have looked as good as ever.
"We have to be more clinical, we have been making too many mistakes," said coach Walter Mazzarri.
"If you look at the other sides fighting for the top places, when they create four chances they convert two of them."
