The Spaniard was frustrated to see his team concede another sloppy goal against Olympiacos in Europe
Mikel Arteta admitted Arsenal "have to stop making errors" after their latest Europa League outing, but also insisted that they won't stop playing out from the back.
The Gunners put one foot in the last eight of the continental competition by beating Olympiacos 3-1 at the Karaiskakis Stadium on Thursday night, thanks to goals from Martin Odegaard, Gabriel and Mohamed Elneny.
However, Arsenal only managed to gain their two-goal advantage after conceding a soft equaliser, with Youssef El-Arabi scoring after intercepting a lazy pass from Bernd Leno, and Arteta has warned his players that they cannot afford to keep making basic mistakes.
What's been said?
The Spanish head coach told BT Sport after the final whistle: "We started the game really well, really dominant and creating a lot of chances.
"We gave them a goal trying to play out from the back but then we reacted well to score two more goals. Overall a really positive result but we have to stop making the errors that are costing goals because we cannot sustain that.
"It isn't about concentration it is about when you play the ball. It is not about stopping the way we play because this is us.
"We were really solid, really dominant. We showed a lot of personality to come here and dominate like we did. The next thing is to do that for 90 minutes and give nothing to the opponent.
"This is half time and anything can happen. Full focus and we start 0-0 again in the second leg and try to win the game."
Leno's moment of madness
There initially appeared to be no danger when Gabriel played the ball back to Leno just outside his own box as Arsenal sought to keep possession early in the second half, but the German shot-stopper picked the wrong option when trying to kickstart another attack.
Leno just about found Dani Ceballos in the middle of the park with a weak pass, but he was being closely marked by two players, the closest of whom was El-Arabi, who was easily able to win the ball back and drive towards the penalty area.
The Arsenal no.1 was then unable to get back into position to stop El-Arabi's subsequent shot, which nestled into the net and left the Gunners defence with their heads in their hands.
When is the second leg?
Arsenal will welcome Olympiacos to Emirates Stadium for the return fixture next Thursday, which will also be played behind closed doors amid the continued absence of supporters amid the coronavirus pandemic.
Arteta's men have a huge north London derby clash to attend to first though, with arch-rivals Tottenham set to arrive at the same venue on Sunday afternoon.