"Merit-wise, performance-wise, there is no question who deserved to win the game," Arteta told reporters.
He added: "It's very difficult but if the team is getting hammered and not deserving to win football matches, I would be much more worried."
Speaking to BBC Sport, the Spaniard said: "Well the performance was there and the amount of chances too. We just have to win the game, but we lost it and we are not capitalising. To win games we need to capitalise. When you are better than the best team in Europe and you generate that amount of chances...I have not seen a team do it against them like we have done it. It is not enough. The reality is, it is not enough. Listen [do I say] play worse than Liverpool, be worse and we will win the game. When my team plays with this confidence what can I do? I am still behind them 100%. "It is what it is and we have to continue to play the same way and be more efficient."