The Citizens were on a 12-match unbeaten run in the Premier League while the Gunners were renowned for crumbling against top opposition - particularly away from home.
So, there was genuine surprise when Arsenal secured a 2-0 victory in Manchester courtesy of goals from Santi Cazorla and Olivier Giroud.
“At Etihad Stadium on Sunday, it seemed that Arsenal manager Arsene Wenger finally realised he cannot play his usual open style of attacking football when his team are away from home against the best teams in the Premier League,” Match of the Day 2 pundit Trevor Sinclair said after the match.
Every other pundit - and supporter, for that matter - thought exactly the same thing. Wenger, it seemed, had finally turned a corner.
Almost two years later, though, and it could be argued that Arsenal haven’t utilised the same smart tactics against top opposition since.
However, there could be an explanation for that based on a text message sent to Chelsea boss Jose Mourinho, from one of Wenger’s players, at the time.
Mourinho expected City to beat Arsenal
Before the match, Mourinho sent journalist Rob Beasley - whose new book, ‘Jose Mourinho Up Close and Personal’, features many revealing tales about the Portuguese coach - predicting Wenger’s men would suffer defeat at the Etihad.
“’Yes was good,” Mourinho said, per the Daily Mail, after his side’s 5-0 win over Swansea City, “‘now let's see s*** Arsenal.’”
After the match, Beasley sent Mourinho a message saying Arsenal had ‘done a Chelsea’ and effectively copied his gameplay.
The current Manchester United boss initially joked: “‘'Mr Wenger gets new 5 years contract’”.
Arsenal player's message to Mourinho
But then came the shock revelation that Mourinho had been messaged by an Arsenal player - who, unfortunately, remains unnamed - explaining that Wenger did nothing to organise the team in the days leading up to the match.
Mourinho’s message said: “‘(One of the Arsenal players) sent me an SMS to say players did themselves, organised themselves during the week. Wenger did nothing.’”
After expressing his amazement, Beasley received another message that his information was “‘100 per cent’”.
This is an extraordinary story on so many levels.
The fact an Arsenal player text Mourinho with this information in the first place, the fact the player in question effectively stabbed his manager in the back by texting a rival coach - and not just any rival coach - and the fact the player felt Wenger had done nothing to prepare the team (tactically, at least) in the build up to such an important fixture.
Do you believe that Jose Mourinho’s text about Arsene Wenger was true? Have your say by leaving a comment below.