Yes, it is clearly not easy to multiply 3 goals against Udinese, especially when they act as a guest club which must get a lot of pressure from the home supporters, but they managed to answer with a victory, even they could create an early goal.
Udinese were not without a fight, they also put a lot of pressure on Juventus and got a few chances, it's just that in this match the Juventus defense worked well so they could secure the goal without conceding even once and gave Szczesny his first cleansheet.
Udinese must recognize Juventus' superiority in this match.
Udinese isn't in fact a bad club nor a good one. It is a team that sits most of the time in the middle of the table with sometimes a victory or a draw vs top teams.
When they face Juventus for example, they are aware that their history contains many defeats vs them so maybe they aren't psychologically prepare to face them.