Two late breakaway goals from Matheus condemned the Gunners to defeat - after they had been harshly denied a penalty as Carlos Vela was booked for diving having seemingly been tripped by Alberto Rodriguez.

Djourou focused on his own team's failings, though, and told Sky Sports 2: "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 knock-out stage."

Two late breakaway goals from Matheus condemned the Gunners to defeat - after they had been harshly denied a penalty as Carlos Vela was booked for diving having seemingly been tripped by Alberto Rodriguez.

Djourou focused on his own team's failings, though, and told Sky Sports 2: "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 knock-out stage."