The boys were held to a frustrating 2-2 draw by Swansea City at Emirates Stadium on Tuesday.
The visitors took the lead on 11 minutes when Wilfried Bony powered a header past Wojciech but the Gunners hit back with two quick fire goals in the second half from Lukas and Olivier.
But in the 90th minute the ball cannoned off Mathieu and into an empty net after Leon Britton broke through on goal.
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