Mikel Arteta revealed that his team's performances will give him "a few nightmares" after they secured a point against West Ham on Sunday.
Alexandre Lacazette scored the last goal forArsenal
in the 82nd minute and as a result, they came from three goals down to guarantee a 3-3 draw against the Hammers at London Stadium.
"[It's] hard to explain,"
The Gunners manager announced toMatch of the Day
after the game.
"We knew the game we would face against West Ham, they can create problems for any team.
"The first goal is something they do really well - the second and third goal, and the chance at the end, is unacceptable. We didn't look at the races."
This means that Arsenal can now hope for a place in Europe next season in such a crowded race, but Arteta confirmed that his team still make it challenging for themselves.
"That is the level we can show, the other is top-level and probably the best we play all season - we could have scored six or seven goals and won the game, but we cannot have two faces.
"We stuck to the plan we had because we were getting further away from that, we started to play much better and I have faith in the boys they are not going to give the game away.
"This game is going to give me a few nightmares because it is really difficult to stop some of the things we have been doing to hurt ourselves."
faced a three-day turnaround before squaring off against David Moyes' team, having been in Europa League action on Thursday,
"I'm very disappointed because I cannot accept my team to play the way we did in periods in the first half,"
he explained toSky Sports
"I expect we play at the level we did afterward."
wondered if the fatigue was to blame for their slow play.
"The first goal, it can happen. It is a really good combination [by West Ham]. That is fine. The way we concede the second and third is unacceptable. I don't know if it's a hangover from Europe, tired, focus, it was more than one player that switched off. We have to right that quick."