Arsenal got William Saliba sent off the field as Bournemouth shocked the Gunners with a 2-0 beating at Dean Court on Saturday.
Saliba saw red in the half-hour as Justin Kluivert and Ryan Christie scored for Bournemouth.
When asked if the dismissal changed the match, Arteta said: “Absolutely. We are very disappointed with the result and gutted because we had to play in that context again. Even more difficult than the previous two that we have faced this season to do it with 65 or 68 minutes with 10 men at this level, it’s just an impossible task.
“It’s an accident waiting to happen not to get the points. I cannot fault the team for their effort, their commitment, to play in the way we had to do it. There was a big moment at 0-0 when we had a one-vs-one with the ‘keeper and we didn’t manage to score. Then at the other end we do that.
“We have to (look at) ourselves. Tonight we made two big errors that cost us the game unfortunately.
“It was a decision made on the pitch. That decision was changed. I don’t think it will change twice. The decision has been made.
“What happens today is almost unpredictable – that the winger is going to play the ball to the centre back one touch, and it’s going to be a challenge there with 40 or 35 metres to go.. Very difficult to plan it. But certainly we need to play with 11vs11 if we want to be in the position that we want to be.”
Arteta added, “Willy has never done anything like this and he doesn’t do it on purpose. Or what happened with the second goal. But it happened. Unfortunately we couldn’t turn it around which is very unlikely for the third time in the season.
“We got away with it twice – the situation was a bit different because we were already ahead in the result. But we have to accept it. Move on and have that pain for Tuesday (in the Champions League). That’s it.”
