Manchester City began 2019 by winning a simply must-win match at home to league leaders Liverpool to reduce the gap at the top to four points.

Sergio Aguero and Leroy Sane got the goals, but manager Pep Guardiola understandably rung the changes for the FA Cup visit of Rotherham United on Sunday.

Vincent Kompany, Fernandinho, David Silva, Bernardo Silva and Aguero were all left out as Man City romped to a huge 7-0 win in the third round tie at the Etihad Stadium.

One of the biggest stories to emerge from the match was the return of the Kevin de Bruyne, whose phenomenal consistency inspired City to the 2017-18 Premier League title.

The world-class playmaker has struggled terribly with injuries this season, however Guardiola has a subtle message for Liverpool after his star man's return and as the title race intensifies.

De Bruyne's frustrating 2018-19 campaign

De Bruyne enjoyed the year of his career last season, recording a superb 12 goals and 21 assists in 52 matches as City won both the league and the Carabao Cup.

However, two significant knee injuries and a recent muscular problem mean the Belgian has only started one Premier League game for Guardiola's side this term.

De Bruyne stars in 7-0 FA Cup win

De Bruyne started alongside Ilkay Gundogan and Phil Foden in midfield against Rotherham and it didn't take him very long to make a meaningful impact.

The creative midfielder, who captained City against their Championship opponents, provided the assist for Raheem Sterling's opening goal after just 12 minutes.

Guardiola's De Bruyne message to Liverpool

In reacting to the 27-year-old's influential display before his 67th-minute substitution, Guardiola warned Liverpool that they've been better than a team that hasn't had De Bruyne.

"I said many times how important Kevin (de Bruyne) is for us," the City boss said, via Sky Sports. "Without him, last season would maybe not have been possible.

“So far, we have done incredible in terms of results, but we have an opponent (Liverpool) that has done better. Fifty points is incredible, it is huge.

“But they are an opponent that has done better than us without him," 47-year-old Guardiola insisted, before adding. "Now he is back.

"He will be fresh in the mind and the legs, and is going to help give us extra in the creativity in the last third, in the fight. Today he was our captain and he showed us why.”

Guardiola certainly has a point in that Man City have managed to keep in touch of Jurgen Klopp's men despite not having their best player from 2017-18 for the majority of the campaign.

With a fit and on-form De Bruyne back, there's every chance that the Citizens could retain their title, but there's a long way to go, and catching Liverpool will not be easy.

Do YOU think City will beat Liverpool to the title if De Bruyne remains fit for the rest of the season? Have YOUR say in the comments box below!