Arsenal manager Mikel Arteta says he "doesn't understand" why Video Assistant Referees are not used in the Europa League after his side were denied what looked like a legal goal against Molde on Thursday evening.
The Gunners beat the Norwegian side 4-1 to continue their 100 per cent start to the competition but suffered a scare when the visitors took the lead after 22 minutes courtesy of Martin Ellingsen's strike.
Arsenal thought they had equalised soon after when Nketiah turned in a low cross although it was flagged for offside.
While Nketiah's team-mate Joe Willock was in an offside position when the ball was played in, he did not make contact with the ball and was not directly involved in the goal. The England U-21 striker applied the finish having been onside - and had the decision been reviewed by VAR, would almost certainly have been given.
Arsenal did eventually equalise just before half-time thanks to a Kristoffer Haugen own goal and ran away with the game in the second 45 minutes after a second own goal, this time from Sheriff Sinyan, and strikes by Nicolas Pepe and Willock.
While Arteta was pleased with the three points, he was confused as to why the Nketiah goal had been chalked off when the technology - used in the Champions League and in top level domestic competitions around Europe - is readily available.
Arteta said in his post-match comments: "I don’t understand, I don’t think it makes any sense when we have the technology and we all believe it is the right call for everybody to do it.
"I don’t understand, and we were complaining with the referee because we were told he was clearly onside and obviously it’s a situation that can clearly change the game. I think it is something they have to look at and, if possible, change it."
Arsenal now have a perfect record of nine points from three games in Europa League Group B, ahead of Molde on six and Rapid Vienna on three. Dundalk, meanwhile, are yet to register a point.
The Gunners can secure a place in the last 32 if they win the return fixture against Molde in Norway. The match will be played on November 26.