The decisive moment in the match came just seconds before half-time when a penalty was awarded after Mehdi Taremi’s strike from a corner hit Merino on the hand.

It was a decision that might not have been awarded in the Premier League as referees have moved away from awarding ‘soft penalties’ from this season.

“Our approach to handball, there’s just a little change and adjustment in where we’re going with it,” former referee Kevin Friend revealed ahead of the season., external

“Last season we saw some soft penalties for handball. So we’re actually looking for examples where the ball clearly hits the arm in an unjustified manner, with the hands above the head, or away from the body to deliberately block the ball going into the penalty area or into the goal.”

That deviates from the rules in UEFA competitions, and that variation left experts frustrated on Wednesday.

Former Arsenal defender Martin Keown told TNT Sports: “Is the arm in an unnatural position? It’s not. We’re having that debate again and it’s ruining the game.”

“It’s fine margins, I don’t think it’s a penalty. The unnatural rule, who makes those rules? Did they play the game?”

Ex-Gunners defender Matt Upson added live on BBC Radio 5: “It pains me how they apply that law in Europe.

“We are miles ahead of that in the Premier League, the referees understand proximity, the speed of the ball and all those things were tick, tick.

“It’s just a bit of common sense.”

Speaking about the incident involving Merino and Sommer at the other end of the pitch, former Arsenal striker Theo Walcott said on Match of the Day: “Merino gets into a good position and (Yann) Sommer comes and gives him a physical clap.

“It’s a shame he didn’t get the penalty and Arsenal were a bit unlucky.”