Analysis: How reliant are Chelsea on Diego Costa? Striker to miss two games in run-in
Diego Costa has been everything Chelsea dreamed of and more when they paid out £32m for the striker from Atletico Madrid.
A goal machine who likes to ruffle a few feathers with his off-the-ball flare ups but a professional who simply just loves to play football.
Chelsea knew buying the Brazilian-born forward came with a few added risks. What of his doggy hamstrings? How long will he stay sidelined through injury? And if it isn't injury, what if one of his tantrums lands him in hot water and the odd supension?
The Spain international has swaggered his way round Premier League defences this season - scoring 19 goals to make him current joint top goalscorer with Tottenham's Harry Kane.
But a recurring hamstring problem looks to have struck Costa and Chelsea at the worst possible time with the 26-year-old expected to be sidelined for the next two weeks - meaning he will miss crucial matches against QPR and Manchester United.
With only eight games left and Chelsea seven points clear of the pack, how will this affect their final charge to the title?
Chelsea's results without Costa
Jose Mourinho's side have been without their talisman for six matches to date this season. When Costa returned from international duty carrying a hamstring niggle back in October, Costa sat out fixtures against Crystal Palace and Manchester United. Chelsea didn't crumble without their hard-man. They picked up three points at Selhurt Park but were denied three points at Old Trafford when Robin van Persie grabbed an equaliser in stoppage time to cancel out Didier Drogba's first Premier League goal since 2012.
A fifth booking of the season ruled him out of a third game of the campaign at home to Tottenham, but in his absence, Eden Hazard, Drogba and Loic Remy again stepped up to the plate to secure a comfortable 3-0 victory.
And even when Costa was handed a three-match suspension for a stamp on Liverpool's Emre Can earlier this year, Chelsea came through unscathed.
Costa watched on as his team played out a nervy top-of-the-table clash with Manchester City which ended 1-1. However, subsequent three points against Aston Villa and Everton helped dispel theories that Chelsea have been over-reliant on their front-man.
Where the goals have come from in Costa's absence
In the six matches without Costa, Chelsea have shared the goalscoring burden among seven different players. Eden Hazard, who spoke of having a "weight lifted off his shoulders" when Chelsea signed Costa leads the way along with veteran powerhouse Drogba and Loic Remy.
Goalscorers in Costa's absence
What of Chelsea's performances without Costa?
In Costa's absence, Chelsea score less goals, an average of 1.7 a game in comparison to the 2.2 when the bustling forward is on the pitch. Their win percentage is up by four per cent when he's playing, with Chelsea holding a healthy 70.8 per cent win ratio in comparison to 66.7 per cent in his absence.
Not surprisingly, without Costa in their ranks their firepower is lacking slightly which is reflected in their shots per game figures, down just over two efforts a match.
But interestingly, where it arguably matters most, the points per game ratio Chelsea remain strong, winning an average of 2.3 points per game with or without their main man.
While Costa's goals have been key to Chelsea's charge to the title, his hold up play and ability to retain possession have also proved the difference to Mourinho's line-up this season.
While Costa has undoubtedly turned Chelsea from nearly men into title favourites this season, Mourinho's side are not putting all their eggs in one basket with one player. Yes, his contribution and goals have been telling but Chelsea have proved on not one but six occasions already this season that when it matters most, they can survive without their talisman.
With the pressure off Hazard this season, the Belgian has struck 17 goals in all competitions while six other players have scored more than a handful this season - a quality any good title-challenging side require.
Even during Costa's dry patch - where he went seven games without scoring - Chelsea had strength in depth to remain unbeaten (although they were knocked out on away goals by PSG in the Champions League) before he rediscovered his shooting touch against Southampton and Hull.
It's hoped that Costa will be fit for the potential 'title decider' at Arsenal on April 26 - but even without him Chelsea have what it takes to deliver a first Premier League title since 2010.