It was a landmark moment for Arsenal's season and possibly for Arsene Wenger's remaining years as the manager as they ran out 2-0 winners over Manchester City.
The Gunners went into the game having taken one point from their last eight trips to both Manchester City and United. They were bemoaned for a lack of defensive stability as they walked out of the Etihad last season having shipped no less than six goals.
It was clear Wenger wanted to focus on keeping a clean sheet. In a very unfamiliar style, Arsenal gave up possession in the early stages in favour of getting men behind the ball.
It worked. David Ospina, again starting ahead of Wojciech Szczesny, had barely a save to make in the opening 45 minutes.
Chances at both ends were few and far between but Vincent Kompany opened the door for Arsenal after blocking the run of Nacho Monreal on the edge of his area. Mike Dean had no hesitation in awarding a penalty, which the growingly essential Santi Cazorla dispatched confidently.
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The second half started with much more fluidity with Arsenal attacking more freely despite holding an unlikely 1-0 lead. A free flowing game was the last thing the Gunners wanted at this stage with Manchester City finally starting to carve out openings.
But Arsenal's luck held out. They kept their clean sheet intact until Manchester City finally lost concentration. Olivier Giroud went unmarked as Cazorla's floated free-kick landed on the Frenchman's head, who buried it in the bottom corner with 25 minutes left on the clock.
But while Cazorla was at his best and Sanchez worked hard, the unlikely star performers for the Gunners were undoubtedly the defensive duo of Francis Coquelin and Monreal.
The former was struggling to get into the Charlton Athletic team in December but kept David Silva–Manchester City's best player by Thierry Henry's reckoning–quite throughout the entire game.
Unlike Aaron Ramsey, who again showed an inability to keep himself disciplined, instead chasing the glory days of last season, Coquelin's performance was measured and composed.
Meanwhile, Monreal was consistent at the back and was rarely found wanting against the tricky Jesus Navas. He started ahead of Kieran Gibbs and has won the right to do so again.
Ospina - 7
Bellerin - 6
Mertesacker - 7
Koscielny - 7
Monreal - 8
Ramsey - 4
Coquelin - 9*
Cazorla - 9
Oxlade-Chamberlain - 7
Sanchez - 7
Giroud - 7
*Man of the match