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Are defensive errors singular aberrations outside the control of a team's head coach, or the consequence of pressure and attrition accumulated due to the temperature of a match?

It is a philosophical conundrum at the heart of football analysis, and one Arsenal watchers will be stewing on after their concession of a two-goal lead at Watford. On a very literal and superficial level, Arsenal dropped two points because Sokratis mis-placed a pass in his own penalty area and David Luiz gave away a penalty with an impetuous challenge. Were it not for those moments of madness, Arsenal and Unai Emery would be third in the Premier League.

Except those moments did not happen in isolation, but in the middle of a second-half in which Arsenal conceded a ludicrous volume of shots, possession and territory to team with one win in their last 10 league games. A half in which Arsenal conceded 23 shots on goal, meaning they have now conceded more shots than any team in the top five European leagues this season (via Opta's Duncan Alexander). That's 98th of 98 teams in England, Italy, Spain, France and Germany. That Arsenal have a uniquely spineless and inept collection of defenders is a well-worn trope, but do their shortcomings as individuals account for that damning statistic? Of course not.