It’s easy to forget that little over a year ago, some pundits questioned whether Barcelona had made a mistake in selling Alexis Sanchez to Arsenal for £35m in the summer of 2014.
Sanchez was a leading candidate to be named Premier League player of the season following 16 goals in his first 28 games for the Gunners, not to mention a further eight assists.
Yet when Barcelona came to visit the Emirates last week as treble-holders with the most prolific attack in Europe, few observers would have believed the Spanish champions could have ever missed the Chilean enduring a torrid run of form.
Sanchez has now failed to score in 11 Premier League games, with a single goal against Championship side Burnley in the FA Cup the only occasion he’s found the back of the net in his last 10 Arsenal appearances.
Furthermore, his assist for Joel Campbell’s opener against Swansea on Wednesday was only his fourth of the season so far.
Sanchez hit the post twice during the game, but it would be as inaccurate as his shooting to put his drought solely down to bad luck.
The Chilean forward’s prowess in front of goal has slowly diminished in the 18 months he has been in North London.
Since returning from a hamstring problem in January, Sanchez has hit the target with 29 per cent of his shots. In contrast, he hit the target 67 per cent of the time at the beginning of his Arsenal career. That dropped to 58 per cent after he received a two-game lay-off in January last year and 55 per cent in the opening months of the current campaign.
Similarly, Sanchez’s success with take-ons has plummeted from 59 per cent last season to just 45 per cent since his recent return from the sidelines.
But it’s not just when he’s got the ball at his feet that he has flattered to deceive in recent outings.
Sanchez won matches with his offensive output last season but arguably won fans’ hearts with the near-demented remorselessness with which he ran, hassled, harried closed down and tracked back.
Imaginatively nicknamed “Duracell” by his teammates, Sanchez’s supercharged hustle is demonstrated in the fact that no forward in Europe’s top five leagues made more interceptions than his 41 last season and only Liverpool’s Roberto Firmino - then of Hoffenheim - made more tackles than his 50.
It all marks a drastic contrast to his sensational start to life at the Emirates which encouraged comparisons to the Thierry Henry’s consistent destruction of defences and accusations of Arsenal being a one man team in the absence of Mesut Ozil.
Yet even when the praises were being sung at their loudest, there were fears sluggish performances would eventually emanate from Sanchez after a gruelling two years during which his debut Premier League season was bookended by the 2014 World Cup and an emotional Copa America triumph on home soil in Chile.
With 4,321 minutes on the clock, Sanchez played more minutes than any other Arsenal player last season - despite Arsene Wenger warning as early as December that his fitness was in the “red zone”.
Wenger has also commented that Sanchez “is the type that you have to hold back because he wants to play every game, but he still has a problem”.
And as frustrated observers at the Emirates will tell you, Sanchez is still not holding back during games - the 27-year-old is averaging more passes per game (and more accurate ones - 83 per cent since returning from injury in January compared to 77 per cent last season) and roughly the same number of take-ons and shots per game.
Yet with a season-defining North London derby to play this weekend, quality of execution as much as willing enthusiasm will be paramount to Arsenal’s hopes of getting their title charge back on track.
Sanchez won’t want to be held back, but it could be in Wenger’s best interests to do so.