Goals from Sergio Agúero and Riyad Mahrez secured a morale-boosting win for Manchester City, as Sheffield United succumbed to a 2-0 defeat at the Etihad on Sunday. 

The visitors had very little of the ball early on but looked more likely to open the scoring, with Lys Mousset in particular proving to be a dangerous out-ball for Chris Wilder's men. 

He had a goal ruled out by a microscopic offside decision from VAR in the opening stages, before he raced onto a long ball and rattled Claudio Bravo's side netting from a tight angle. 

​City weren't playing particularly well, but they did manage to get their noses in front shortly after the break, with a contentious opener from ​Sergio Agúero. The visitors felt referee Chris Kavanagh should have stopped the play after he inadvertently touched the ball in the build-up, but neither the official or VAR were interested in ruling it out. 

From there, they didn't quite put United to the sword, but there was a clear uptick in the champions' sharpness in the final third. It took another 30 minutes for the decisive second to arrive, but arrive it did, when the Belgian played a one-two with Riyad Mahrez before wrong-footing Dean Henderson with a powerful near-post drive.

Sergio Aguero,Riyad Mahrez,Raheem Sterling

United were desperately unlucky not to pull one back when Billy Sharp's header hit the post in stoppage time, but 2-0 it would stay, as City recovered from a serious blow with an important win. 

Manchester City

Key Talking Point

In order to stand any chance of retaining their Premier League title, City kicked off the second half of their season in the knowledge that nothing but absolute perfection in the 19 games alive would do - and even that, in all likelihood, would not be enough. 

Still, they were always going to try, weren't they? In a bid to get things back on track, Benjamin Mendy and the suspended Ederson - whose costly individual mistakes were chief among the reasons behind that Friday night defeat - each made way for Oleksandr Zinchenko and Claudio Bravo, while 18-year-old Eric Garcia was handed a full league debut for the rested Nicolas Otamendi. 

Lys Mousset,Eric Garcia

They were pedestrian in the first half, perhaps owing to fatigue after a quick fixture turnaround, but they controlled possession throughout, and with the quality they have in their ranks, an opening goal is never far away. And so it proved shortly after half-time, when Kevin de Bruyne and Sergio Agúero combined for a trademark City opener. 

The champions were far from at their best, but De Bruyne would make sure of the points with an impressive second, and it's a win that will go a long way to restoring some pride to the damaged egos of a team now just the 14 points off top spot. 

Player Ratings

Starting XI: Bravo (6); Walker (6), Garcia (8), Fernandinho (6), Zinchenko (7); De Bruyne (8), Rodri (6), Bernardo (5); Mahrez (7), Aguero (6), Sterling (6)

Subs: Gundogan (6), Foden (6)

Star Man - Eric Garcia

City didn't exactly have swathes of defending to do against the conservative visitors, but they had to be switched on at the back against a side who did pack a real punch on the counter. 

That being the case, a big performance was required from an 18-year-old making his first league start at the heart of the back four, and Eric Garcia came up trumps with a composed, commanding display. 

Phil Foden has long been touted as City's chief star in the making, but with their defensive injury issues what they are at present, he may now have a rival for that crown.

Sheffield United

Key Talking Point

Disciplined, organised, tactically intelligent and carrying enough of a punch in the final third to hurt anyone on their day, Sheffield United have been one of the stories of the season so far, and came into this one with cautiously optimistic hopes of another famous result - but had it all to do against a wounded animal ten times their size at the Etihad. 

Still, defeat isn't something they had tasted often since returning to the Premier League, and if they were to take a fifth defeat in 20 top-flight games on the chin here, then it wouldn't be without a fight. They had lost just once in the 13 games since Liverpool's narrow win at Bramall Lane, and in the early stages of this one they showed no signs of subservience. 

Riyad Mahrez,Jack O'Connell

Their inferior quality in comparison to the former centurions eventually shone through, but you'd be remiss in giving them a pat on the head. Some slack defending combined with bad luck in the final third ultimately cost them, but it's hardly a disaster in the scheme of things for a side who have every reason to believe they are just getting started back in the top flight. 

Player Ratings

Starting XI: Henderson (6); Basham (7), Egan (7), O'Connell (6); Baldock (6), Besic (6), Norwood (6), Fleck (7), Stevens (6); Robinson (5), Mousset (8)*  

Subs: McGoldrick (6), McBurnie (6), Sharp (6)

Star Man

It was a tough afternoon for the Blades, who saw just over 25% of possession over the piece, but things would have been far tougher if not for the formidable escape route that is French striker Lys Mousset.

On another day, the affectionately-named 'Moose' would have had a couple of first half goals to his name. He'll have far better days in terms of his finishing, but his pace, control and physicality were essential in driving his side forward on the break and assuring the traffic wasn't all going one way. 

Looking Ahead

Manchester City kick off 2020 with the visit of Everton on New Year's Day, before hosting Port Vale in the EFL Cup three days later. 

Sheffield United, meanwhile, follow this one up with an unenviable trip to Anfield, before their FA Cup campaign starts with the visit of non-league side AFC Fylde. 

For more from Robbie Copeland, follow him on Twitter!