The Terriers improved in the second half and got a late consolation with a Sead Kolasinac own goal but it was not enough as they slipped to a 19th defeat of the season to remain rooted to the foot of the table and heading for inevitable relegation.
Gunners boss Unai Emery said, "I am very happy. We were working very well and every player was working and helping each other. Today I am very proud with our work, every player worked. I want more every time, because in the first half the difference between them and us was two goals, and it is not enough, because if they score one they can get more.
"My ambition is to want them to keep the mentality and don't concede the position to the opposition. But I know it's easier on the bench than on the pitch but today I think the players worked well."