Mesut Ozil and Alexis Sanchez – who now has 23 for the campaign – were both on target.
Ozil and Sanchez are still yet to commit their futures to the club.
Arsenal player ratings against Middlesbrough Mon, April 17, 2017
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Petr Cech – 7: Made a crucial save when the defence failed him
Mesut Ozil and Alexis Sanchez are yet to decide their Arsenal futures
Arsene Wenger's men won away for the first time this year
Who knows? We are in a position where we want to perform – you can always find explanations
Wenger meanwhile, has an unsigned two-year contract on the table, but the club’s recent form has seen him incur the wrath of the fans.
But when asked whether off-the-field issues were hindering his side, Wenger said: “Who knows? We are in a position where we want to perform – you can always find explanations.
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“We are professional people and our job is to perform despite difficult situations that lack clarity."
Arsenal are sixth in the table, seven points off fourth-placed Manchester City.
Middlesbrough, meanwhile, are six points adrift of safety.