Mikel Arteta decided to play Rúnar Alex Rúnarsson instead of Bernd Leno for Arsenal's Carabao Cup quarter-final against Man City on Tuesday evening.And that decision was not wise.The Icelandic goalkeeper produced some questionable goalkeeping for Man City's opener after two minutes.He came to punch out a cross but got nowhere near it as Gabriel Jesus headed home.And he made a disastrous error in the second half.Rúnar Alex RúnarssonMan City were given a free-kick in a dangerous area eight minutes after the restart.Riyad Mahrez's effort was straight at Rúnarsson and it looked like he would make an easy save.But he couldn't hold on to the ball as he produced a howler.Watch it below:

That is an absolute shocker.

Runarsson said earlier this month that he had aspirations to become Arsenal's number one goalkeeper.

“Yes, 100 per cent. Otherwise I wouldn't be playing for this club," he said when asked whether he was capable of challenging Leno for a starting spot, per Goal.

“That should be the mindset for everyone, that you want to play.

Rúnar Alex Rúnarsson

“It doesn't matter what position you play. Maybe as a goalkeeper it's a little bit different but definitely you have to have the mentality to push to become No.1.

“If it happens in one week or one year that always has to be your mentality otherwise you're in the wrong profession I think.”

“I have to have this mentality that I can play and I have to believe it.”

Leno won't be worried about losing his position to Runarsson after his display on Tuesday, that's for sure.