Diego Costa has not scored for Chelsea in nearly NINE hours of football

Should we be worried about the Spaniard's lack of goals recently?

Diego Costa has a long-standing hamstring injury (Getty Images)

First things first: Diego Costa did not score against Tottenham in the Capital One Cup final.

As much as the Spanish striker would want the goal (and Spurs defender Kyle Walker would happily give it to him), Costa was clearly intending to cross the ball for Ramires at the far post - the ball is travelling towards the centre of the box and Hugo Lloris takes a faint step to his left to anticipate the ball travelling in that direction.

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That own goal leaves the Chelsea striker with a slight cause for concern: he hasn't scored since the demolition of Swansea on 17 January, 529 minutes or 11 minutes shy of nine hours.

Given his start for the Blues and his rapid ascension to the top of the scoring charts, should there be any concern from Jose Mourinho that his main man is not finding the net?

There are mitigating circumstances, of course. In the six games in which he's failed to score Chelsea are unbeaten, with three wins and three draws. They've played some tough opponents in that time Liverpool twice in the semi-final, Paris Saint-Germain away, beating Spurs to win the League Cup and West Ham away.

Chelsea's draw against Burnley was disappointing, but Mourinho's 10 men should have had two penalties and the Clarets a man sent off. Chelsea also drew with Manchester City and won their two other games while Costa was suspended.

Diego Costa may have celebrated against Spurs but it wasn't his goal (Getty Images)

But it's the form of his team-mates that is in question, it is the man himself, who appears to be slowing down slightly after a blazing start.

Against West Ham last week Carl Jenkinson recovered brilliantly to provide a last ditch tackle when Costa appeared through on goal - but the Spaniard hesitated slightly where earlier in the season he may have taken the chance quicker.

In these six matches he has managed just eight shots, with a paltry two on target. In his previous 26 games for the Blues, Costa had had fired in 77 shots, with 39 hitting the target, taking his average from 2.91 shots per game down to just 1.33.

It's a small sample size and Mourinho admitted he would be rusty after that three-game suspension, but if it continues much longer it may turn into a worrying trend; Costa is yet to score in seven Champions League appearances (five starts) this season also.

In other facets of his game he is still the same beastly nuisance that no defender wants to face. He plays the lone role to absolute perfection, holding the ball up and bringing team-mates into the game, winning his fair of aerial battles and generally winding up defenders and throwing them off his game.

Cesc Fabregas has not notched an assist in eight matches (GETTY IMAGES)

Some of the blame can also be laid at the feet of Cesc Fabregas, who has also just slowed slightly in recent weeks. After jumping out to lead Europe with 15 assists, Fabregas has not recorded one since that same game at Swansea on 17 January.

The midfielder has now gone eight games without providing a goal - although some of that can rest with wayward finishing. Fabregas has struggled with a hamstring problem and then illness recently and hasn't been at his devastating best.

A move to the quicker-paced Premier League, where more games are played at a higher intensity, looks like it's starting to take it's toll on both of these players.

But Jose Mourinho won't be worried and neither should Chelsea fans - the Blues are in a perfect position at home and abroad heading into the last two months of the season.