
Neither side had conceded a goal in their opening three games in the competition but Arsenal’s defence was finally breached in unfortunate fashion on the stroke of halftime after a harsh handball decision against Mikel Merino.
Calhanoglu has now converted 19 out of 19 penalties in all competitions since joining Inter.
Arsenal laid siege to the Inter goal in the second half with Kai Havertz denied by home keeper Yann Sommer and having another effort deflected just wide, but Inter defended superbly to move to 10 points from four games.
Mikel Arteta’s Arsenal are outside the top-eight automatic qualifiers for the knockout phase with seven points.