Arsene Wenger slams his side for their weak 'mental level' and defensive mistakes as Arsenal throw away three-goal lead against Anderlecht in Champions League 

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Arsene Wenger lamented Arsenal's weak mentality and poor defending as the Gunners threw away a three-goal lead to draw 3-3 with Anderlecht in the Champions League.

Arsenal led 2-0 at half-time thanks to Mikel Arteta's penalty and Alexis Sanchez's stunning volley before Alex Oxlade-Chamberlain looked to have sealed the win with a third before the hour.

There was late drama, however, as Anthony Vanden Borre scored twice - the second another spot-kick - and Aleksandar Mitrovic headed in a 90th-minute equaliser to snatch a dramatic point for the Belgians.

Nacho Monreal, Lukas Podolski and Tomas Rosicky (left to right) trudge off after Arsenal threw away a three-goal lead at the Emirates to draw 3-3 with Anderlecht on Tuesday in the Champions League

Aleksandar Mitrovic scored a 90th minute equaliser to break Arsenal hearts and steal a point for his side

Arsenal manager Arsene Wenger slammed his side for their weak 'mental level' against Anderlecht

'Maybe we underestimated them subconsciously and we got punished - in the Champions League you need to be at the right mental level and we got punished because we were not,' Wenger said.

'You have to give them credit - they tried until the end.

'We had a poor defensive performance from the first minute to the 90th today.

'We were also punished because of bad luck - the first goal was clearly offside - but defensively our performance was not good enough. We thought the job was done.'

Arsenal's misery was compounded by the sight of Arteta hobbling off in the second half with what Wenger revealed is a hamstring injury.

Santi Cazorla attempts to help Alexis Sanchez of the turf after the comeback from Anderlecht

The Gunners remain in a strong position to qualify from Group D but their chances of finishing top of the pool are slim with Dortmund now five points clear.

Wenger's side have gone through second in three out of their last four European campaigns and have lost in the last 16 on each occasion.

'We dropped off too much in the second half and didn't go into the challenges any more - then you are always open,' Wenger continued.

'We stopped winning the challenges and dropped off. We didn't stop the crosses, we didn't stop the long balls.

Mitrovic beats Per Mertesacker to a near-post header to complete the most unlikely of comebacks

'In the first half we were outnumbered sometimes but in the second half it was bad defending.'

Anderlecht exacted sweet revenge for Arsenal's victory in the reverse fixture a fortnight ago, when the Gunners scored twice in the last three minutes to win 2-1.

The young Belgian outfit were a threat on the break throughout the contest and Wenger admits he was impressed with his opponents.

'Anderlecht are a good team,' Wenger said.

'Maybe in four or five years we will see this team was full of good players and they are much better than everyone thinks they are.'

'Even in the first half they had three or four good chances - they are a good side.'

Arsenal face Dortmund at home next before their final group match away to Galatasaray.

Aaron Ramsey lies face down on the turf during Arsenal's draw with Anderlecht