Johan Djourou has urged Arsenal to eradicate their 'silly mistakes' after the Gunners lost 2-0 at Braga in the UEFA Champions League.
Arsenal slumped to a late defeat in Portugal to leave them level on points with Braga in Group H ahead of their final game against Partizan.
Djourou was disappointed with the manner of his side's loss, highlighting the team's lack of concentration as they were undone in the latter stages.
The Switzerland international told Sky Sports: "It's crazy.
"We had the game under control and two counter-attacks and silly, silly mistakes - we can be disappointed because we should have won the game easily, it's very hard to take.
"A point would have qualified us so it's a shame to concede goals like that, I just cannot understand. We have to look again, that shouldn't happen. It was a lack of concentration, the team needs to concentrate and do better than that.
"The team needs to know that now we have to wake up, it was a big wake-up call.
"We have a big game against Partizan and we have to win that to qualify for the knockout stage."