
Branislav
Ivanovic, Cesc Fabregas and even Eden Hazard have been among those
criticised by Chelsea boss Jose Mourinho in the opening weeks of the Premier
League season.
However, the form of star striker Diego Costa is a serious concern, too.
Here, WhoScored.com look at the stats behind the Spaniard's slow start to
the campaign…
At this stage last season Chelsea were already three points clear at the top
of the Premier League, having scored 16 goals. Summer signing Diego Costa
had seven of those goals and had hit the ground running, tormenting defences
with his gritty, aggressive approach to leading the line.
Costa settled into Chelsea's system seamlessly along with fellow newcomer
Cesc Fabregas, with the two quickly developing an understanding that saw the
latter pick up more assists for his international team-mate (six) than any
other pairing in the league last season.
Of course, the midfielder's well-documented decline since the start of the
year has seen Costa's influence wane in turn, but both are culpable for
failing to get anywhere near the admittedly astronomical standards they had
set this time last year. Costa has just one goal from seven games for club
and country this term.
The fact that Chelsea's opponents over the first five games of the previous
campaign and this are so similar only serves to highlight the pair's
downfall.
The Blues have faced Swansea, Manchester City and Everton, just as they had
at this stage last season. However, while Costa scored five times against
those opponents last season, he's drawn a blank against them this time
around.
Much of the predatory instinct that had made Costa such an instant success
has looked to be absent for some time now.
A no frills striker, the former Atletico man is at his best when not trying
to complicate matters. Twelve months ago he was shooting at any given
opportunity but now he is trying to make scoring chances easier by having
that extra touch. Not only is it having the opposite effect but it is a sign
of a player lacking the confidence to chance his arm early.
One of very few chances against Everton at the weekend saw him try to check
onto his stronger foot after being laid in, admittedly too late, by Ivanovic
on the counter. Previously he might have steadied himself before firing a
shot at goal early but he dallied and was ultimately dispossessed. It summed
up Costa's current issues in front of goal and was indicative of a player
overthinking things in the box.
After five matches in 2014 Costa had mustered 16 shots at goal; he's managed
just nine this time around. More pertinently though, at this stage last
season he had already hit the target 11 times having done so just three
times so far in 2015/16.

Moreover,
the Spain international's average figures for key passes, dribbles and
aerial duels won are all down, contributing to a substantial dip in his
WhoScored.com rating.
After five games in 2014/15 Costa was the Premier League's highest rated
player with a score of 8.37. A year on and a rating of 6.71 is enough to
rank joint-167th out of the 269 players to feature at least three times,
tied with Fabricio Coloccini and, ironically, Cesc Fabregas.
Of course a five-game sample size is very small indeed and taken in
isolation could represent a common dip in form. However Costa, like
Fabregas, has not looked at his fearsome best for some time now and his
consistent fitness concerns, coupled with question marks over Chelsea's
depth in attack, will be a genuine concern for Mourinho.
After seven goals in his opening four league matches for the club, injuries
dictated that it took Costa the entire second half of last season to match
that tally. With just one this time around, as well as continued struggles
on the international scene, the front man is nowhere near as intimidating a
prospect to face as he was upon his arrival at the Bridge.
He may not be getting the same quality of service he once was, but Costa
doesn't look as sharp physically or mentally as he needs to be if Chelsea
are to complete what is nearing a seemingly impossible turnaround.