Whatever one might have to say about Diego Costa's abrasive, borderline explosive character, there has seldom been doubt about his proficiency in and around the penalty area.
But as his painful drought continues the question must be raised: just what is going wrong for the Atletico Madrid favourite?
Costa made an instant impact at the Wanda Metropolitana at the start of 2018, as he sealed a move away from Chelsea amid a brutal falling-out with former boss Antonio Conte.
Atletico's decision to bring him back to the club where he starred prior to that move to Stamford Bridge appeared a masterstroke.
The Spain international netted in his first game back under the watchful eye of Diego Simeone and continued to impress as Atletico consolidated a laudable second place in La Liga ahead of city arch-rivals Real Madrid, ensuring yet another season of Champions League football. But almost imperceptibly, the goals were drying up.
Eighteen games and a whopping nine months have passed since Costa's last goal in La Liga for Atletico.
One must look back all the way to February 2018 to find that strike, a dismal record for one of Europe's most potent forwards, even considering a succession of injury struggles that have affected his continuity in the Atletico line-up.
Getty/Goal
In total, Costa has hit the net on just three occasions in 2018-19; once if you discount the double netted against Real Madrid in the UEFA Super Cup at the start of Julen Lopetegui's short, unhappy reign at the Bernabeu.
That drought is hurting a side that is not exactly blessed with free-scoring players – Antoine Griezmann is their top Liga scorer on a paltry three, just ahead of defenders Diego Godin and Filipe Luis.
As a result, Atleti are leaning more than ever on their exceptional defence and, in particular, goalkeeper Jan Oblak, to stay competitive domestically and in Europe.
Costa's numbers for the current season point to a chronic lack of service. In La Liga, he averages just one shot per game, a rate closer to centre-back pairing Godin and Jose Maria Gimenez than Griezmann or even midfield star Saul Niguez.
However, while he has been starved of support and forced to forage for openings far from the opposition net, Costa also hasn’t shown the initiative to make his own chances, preferring instead to play off Griezmann and feed off whatever scraps fall his way.
It is that seeming apathy, so uncharacteristic of this fiery character, which causes the most concern in the Atletico ranks, and which has seen him fall out of the reckoning for Spain as well.
Juan Campillo, a sports psychologist who has worked with Costa and Spain, has argued that recent injury problems have led to a drop in his intensity.
"He has a character in which he can show his best side being aggressive and even a little annoyed,” Campillo explained to Telemadrid in the build-up to Saturday's crunch title clash at home to Barcelona.
"We all know as well about how he demands more of himself, the way he prepared when he came back from a period in which he was inactive.
"Just as I saw Diego in the national team as a complete, centred individual, I think he has it under control.
"Once the injuries fade away and he gets continuity in training and in games, he will be back to his best."
Atletico believe that the international break has done their volatile forward a world of good.
Having played just two Liga games since the start of October, Costa has been passed fit to face Barcelona on Saturday and, if all goes well, will line up once more alongside Griezmann to take on a Blaugrana defence which could at best be described as shaky in 2018-19.
It is the kind of high-profile game the Brazil-born forward revels in, where his intensity and aggression can pay dividends.
Atletico will be hoping that he has turned a corner and is ready to run Barca ragged in a game that, even at this early stage, could have major implications for the title race come May 2019.
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