Arsenal's unbeaten run in this season's Champions League was brought to an end by a controversial first-half penalty as Inter Milan won at the San Siro.

The hosts were awarded a spot-kick seconds before the break when Mikel Merino was deemed to have handled the ball, although there was little he could do to move out of the way of Mehdi Taremi's flick on.

But the decision stood after a check by the Video Assistant Referee (VAR) and Hakan Calhanoglu confidently sent the penalty down the middle.

It was the first goal Arsenal had conceded in Europe this campaign but they still had plenty of time to equalise, and they went close after the break but Dumfries cleared Gabriel's header from a corner off the line.

Arsenal continued to dominate in the second half, with Inter goalkeeper Yann Sommer pulling off a superb one-handed save to keep out Kai Havertz's curling shot.

Havertz again went close as the Gunners pushed, this time seeing an effort blocked superbly by Yann Bisseck.

But Mikel Arteta's side suffered their first loss in four games in Europe this season, a result that leaves them 12th in the 36-team league.