Chelsea were not discussed as Premier League title contenders before the season began.

It was expected that the club would have a transitional period due to the arrival of Maurizio Sarri as Antonio Conte's successor.

However, so far the Blues have exceeded expectations and they currently sit second in the standings on level points with leaders Manchester City.

Eden Hazard and his teammates have adapted well to Sarri's system but Sky Sports pundit Paul Merton believes that they would be certain of a title challenge if Diego Costa was still at the club.

The controversial striker, who is valued at £54m by Transfermarkt, forced a return to Atletico Madrid in January after falling out with Conte.

During his three-and-a-half-year spell at Stamford Bridge he scored 58 goals and registered 24 assists in 120 matches.

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At the moment, Hazard is Chelsea's top scorer with seven goals, but strikers Alvaro Morata and Olivier Giroud are struggling.

The former has managed to find the net only twice, while Giroud is yet to get off the mark.

While speaking on Sky Sports' The Debate, Merson suggested that Costa would make a difference in Sarri's side if he was still at the club, but is he right?

Let us know by voting below.