Henry entered the game in the 68th minute, as Arsenal was struggling against its opponents from the Championship. The Gunners' all-time leading scorer took just 11 minutes to live up to the script.
He collected a pass from Alex Song, took one touch and hit a side-footed shot to the far post as he has done so many times before.
The 34-year-old is on loan from the New York Red Bulls. He rejoined Arsenal on a short-term deal (believed to last six weeks) last week, and made an instant impact in his first game in English soccer since 2007.
Arsenal will host Aston Villa in the FA Cup fourth round on Jan. 28 or 29.