Fernandinho, Kevin De Bruyne and Sergio Aguero were on target as Pep Guardiola and Manchester City continued their relentless march towards the Premier League title with a 3-0 win at home to struggling West Bromwich Albion on Wednesday.

Despite injuries in his squad, and the decision not to press on with the signing of Leicester's Riyad Mahrez, the victory marked a successful end to the month for City who have now opened up a 15-point gap at the top of the table.

Hours before kick-off, Guardiola had given up on his pursuit of Mahrez after the Foxes turned down a reported offer of £65 million ($92 million, 74 million euros).

But City did hand a debut to one transfer window signing, the French central defender Aymeric Laporte, who signed from Athletic Bilbao for a City club-record £57 million just 24 hours earlier.

It was a rusty start for the 23-year-old, featuring a couple of mis-hit passes but, otherwise, it was business as usual for the league leaders even though they were without the in-form Leroy Sane, injured in the weekend FA Cup win at Cardiff.

City were dominant from the start, England goalkeeper Ben Foster making a timely save at the feet of Sergio Aguero as he pounced on a Raheem Sterling cross.

David Silva struck a free-kick directly into the wall and Foster had a couple of anxious moments when required to punch away De Bruyne's opportunistic effort.

It was hardly a shock, therefore, when City took the lead in the 19th minute following yet another magnificent through ball from De Bruyne.

The Belgian's weighted pass played his Brazilian team-mate goal side of Gareth McAuley and Fernandinho produced a clinical finish past Foster from the corner of the six-yard area.

City should have doubled the lead minutes later, when Silva centred from the left-hand by-line through the six-yard area, but Aguero hesitated, and De Bruyne, of all people, was guilty of a rare error when played clean through on goal, with the midfielder shooting directly at Foster.

De Bruyne also shot over from an Allan Nyom clearance and brought another fine stop out of Foster after setting up an opening with a neat move involving Aguero.

Ilkay Gundogan, on for the injured David Silva, helped set up an early second half chance from which Sterling should have settled the outcome but the England forward curled his attempt wide.

Aguero maintained the pressure, with a clever piece of improvisation, as he back-heeled Bernardo Silva's cross and found Foster alert once more.

City piled yet more pressure on Foster, who did well to parry Bernardo Silva's 18-yard shot, before Oleksandr Zinchenko's 25-yard shot flew just wide.

But, while they struggled to break down Albion's massed defence, there was no such problem on the counter-attack, from which City scored their second goal in the 69th minutes as Gundogan led the charge.

De Bruyne took the ball on, being fouled by James McClean but continuing, exchanging passes with Raheem Sterling and converting impressively into the right-hand corner from a dozen yards.

De Bruyne was obviously inspired by McClean's crude lunge -- one which, correctly, earned him a booking -- and moments later attempted an audacious chip from just inside the Albion half which had Foster back-pedalling furiously and tipping the ball over for a corner.

Substitute Brahim Diaz and Bernardo Silva almost scored from yet another counter before Aguero made it 3-0 in the final minute with an impressive chip over Foster after Sterling had played him into the Albion area with a selfless pass.