Theo Walcott’s first-half goal was enough to give Arsenal the advantage over Udinese going into the second leg of their Champions League play-off tie.
The winger volleyed in Aaron Ramsey’s right-wing cross from close range to give the Gunners a fourth-minute lead.
Udinese went close on several occasions with the influential Antonio Di Natale striking the bar with a free-kick and scraping the post with a low shot.
Pablo Armero and Mauricio Isla had goalbound efforts blocked.
It was a tense, nervy night but Arsenal take a first-leg lead to Udinese in the return leg next week.