Manchester City kept the pressure on Premier League leaders Liverpool with a 3-1 win against Arsenal on Sunday afternoon. 

It was a Sergio Aguero hat-trick that sunk the Gunners at the Etihad.

He's now scored three or more times in an impressive 10 league games and only Alan Shearer boasts more than that in the Premier League era.

It was a great day for Aguero and Man City then, but a frustrating one for visitors Arsenal. 

Unai Emery's team have slipped to sixth in the table, as Chelsea have regained their fourth spot and Manchester United have now jumped above them. 

Following the final whistle, many fans concluded that Arsenal lacked that spark they needed to really challenge City and some even put that failure down to Emery's team selection. 

OZIL'S OMISSION

That's because once again, Mesut Ozil didn't feature. The midfielder was named on the subs bench but Emery decided not to use him.

The manager's reluctance to play the German, who is Arsenal's highest earner, has baffled fans for a few months now. 

And after the north London side were outplayed on Sunday, supporters are growing more frustrated than ever. 

But what Ozil was caught doing in the tunnel at half-time during City vs Arsenal might just annoy fans even more than Emery's decision making. 

SWAPPING SHIRTS 

While making his way back to the dressing room, the midfielder was spotted in conversation with Leroy Sane by City's 'tunnel cam' and was holding his unused shirt.

The camera then cuts to a different angle, and Sane is seen walking up a set of stairs with Ozil's shirt in his hands, which suggests the Arsenal star gave it away. 

Check it out by skipping to the five minute mark in the video below. 

Of course, it's normal for players to swap shirts - but they should be doing it on the final whistle, not at half-time. 

And this isn't the first time that Ozil's been guilty of giving his shirt away early. Back in 2015, he was criticised by Paul Scholes for doing the same thing during a Champions League tie with Monaco. 

There's no rule against swapping shirts at half-time, but as Arsenal were losing to City and the two sides were locked in a battle on the pitch, Ozil's actions will undoubtedly frustrate fans once again.