Diego Costa's importance to Chelsea is unquestionable. The Spanish striker has netted 32 Premier League goals over the past two seasons.
And the 28-year-old has already netted ten this campaign, which currently sees him joint top of the scoring charts, alongside Manchester City's Sergio Aguero.
The league's current joint top scorers will have the chance to go head-to-head at the Etihad on Saturday, when Antonio Conte's men travel to face a City side that are currently a point and two places behind the Blues.
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But former Chelsea star Salomon Kalou, who spent six years at Stamford Bridge before leaving the club for Lille in 2012, believes that Costa is so vital to the Blues that his form alone could dictate where the title ends up at the end of the campaign.
Last season did not truly compare to Costa's first campaign in England, as Chelsea endured a woeful campaign which saw them fail to qualify for a place in Europe. But Kalou told Goal that he believes if the Spaniard finishes top scorer, the Blues will also finish top.
"Diego Costa did well already under [Jose] Mourinho," said Kalou. "But he didn't quite have the same quality last year as he has shown this year. He needed new motivation and that is what Conte brought to him.
"If Diego Costa is top scorer then they will win the league; it works the other way around as well. The two go together. Eden [Hazard] is a great player too; he can do anything with the ball.
Costa and Hazard vital
"He is carrying the team with Diego Costa. He is important but he requires the whole team to be amazing. When the team plays amazing, it is easy for him to go forward and to score."
But while it may seem a bit drastic, on the surface, to believe Kalou's theory that if Costa tops the scoring charts Chelsea will win the league, the west Londoners' record suggests that could prove to be true.
Conte's men boast the joint meanest defence in the Premier League, alongside Tottenham, while they are only three goals shy of the league's top scorers Liverpool.
Costa's influence is unquestionable for the Blues and Kalou believes his former club have put their horrific campaign last season behind them and are ready to regain the Premier League trophy.
Blues possess the fight
"Chelsea can win the league, of course, because they started very strong; they have shown that they have the fight for the title. They have great character." Kalou added.
"This team has done something difficult - come back from last season where they had a bad time and shown a winning character. I am sure that they have the chance to win it."
Costa will not only be hungry to prove that his Chelsea side are back to their best, but will hope to settle a personal battle with Aguero at the top of the scoring charts, with the Argentine having been one of the league's highest scorers for a number of years.
And after a brief blip in September, which saw Conte's side lose to both Arsenal and Liverpool, Kalou can only see positive progression for Chelsea from now on, under the Italian's leadership.
"They are doing very well under him." Kalou added. "He has got them playing great football, not conceding goals, improving game by game so you can only be positive, looking at how well Chelsea are doing this season."
Could Chelsea maintain their Premier League title challenge without Diego Costa? Have your say in the comment box below.