The north London side seized a Champions League lifeline to record their first win of the campaign against Pep Guardiola’s Bayern outfit.
Substitute Olivier Giroud broke the deadlock in the 78th minute before Germany international Mesut Ozil added a second in the fourth minute of injury time.
Mertesacker, who started at centre-half alongside Laurent Koscielny in north London on Tuesday, took to Twitter to pay tribute to the home supporters.
— Per Mertesacker (@mertesacker) October 20, 2015
Arsenal lost to Dynamo Zagreb and Olympiacos in their opening two Champions League games before a vital 2-0 win against Bayern to kick-start their European campaign.
The Gunners make the return trip to the Bundesliga champions next month.
Arsenal have won their last three games in all competitions following victories over Manchester United, Watford and Bayern.
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