In what looks set to be the biggest talking point of the weekend in the Premier League, relegation battlers Burnley recorded an almighty upset in the form of a 1-0 win over reigning champions Manchester City.

Although the Citizens have the best record of any club against bottom half sides in the division this term, such disappointing displays against lesser opposition have become worryingly regular for the Etihad outfit.

Facing an ageing squad with an often complacent mentality, we at Football Fancast think Man City need a serious shake-up this summer via the transfer market - although manager Manuel Pellegrini is now almost certain to be booted out the exit door too.

And with that in mind, here's three reasons the Sky Blues desperately need a summer shake-up, as evident throughout the ninety minutes this afternoon.

A DIVINE RIGHT MENTALITY

It's been said of Manchester City before and certainly rung true this afternoon, they often enter fixtures against lesser sides with the dangerous assumption that they're going to win - a divine right to victory, if you will.

Nobody can doubt the SkyBlues' quality, but quality alone is not enough in the Premier League and once again, it was as if the visitors expected that to be all they needed to see them surpass a well-organised, highly motivated Burnley side.

The City board were quick to oust Roberto Mancini after the club's complacent title defence in 2012/13, but a behavioural trend that's now seeped into Manuel Pellegrini's reign too, one can only point to the mentality in the dressing room.

Although few dispute City to be the most talented team in the English top flight, they continually lack the work-rate, desire and teamwork to match.

AN AGEING SQUAD

Age is just a number, but it should be a troubling one for Manchester City. They currently boast the oldest squad age in the Premier League, 29.6 years, and the average age of all their players involved today was a worrying 29.

Not only does that reflect on City's inability to bring academy players through to the first team in recent years, but it also highlights the club's desperate need for fresh blood. The daunting alternative is the entirety of the squad surpassing their peaks and needing replacing at the same time, which would undoubtedly require a Financial Fair Play-bending sum of money.

THEY NEED A FEW MORE GEORGE BOYDS

George Boyd may not be the most glamorous player in the history of the Premier League - in fact, only last summer was he deemed not glamorous enough for Hull City.

But what's not to like about this lad? He's home-grown, has good technique and an absolutely impeccable work-rate, a combination of which made him the match-winner this afternoon.

The 29 year-old not only scored the deciding strike in the 1-0 affair, but he also made the most tackles of any Burnley player, as shown below:

In fact, he ranks in fifth - yes, fifth - in the Premier League's tackle rankings and is the only forward in the top ten. Not bad for a January bargain.

If City had a few more players of Boyd's mentality in their midfield, prepared to work for their moments of glory, perhaps banana-skin results of today's magnitude would be a lesser occurrence.