Udinese is not a weak team. This team often surprises everyone with good performances. And I have seen Udinese players perform well against big teams in several matches. Udinese managed to score 2 goals in the home match against Inter Milan. Although Udinese failed to win the match, Udinese's performance was still good.
Seeing and considering from the ranking, Udinese is indeed a middle club in Serie A. And even in the last 2 matches, the results were not so good, only 1 loss and draw. But before that, they were quite optimal.
But what makes it different is the fact that Udinese has made top clubs win matches several times, either making them draw or lose.