Despite all their improvements under Unai Emery, Arsenal’s defensive state is still extremely fragile due to a real lack of quality.

Even when they're poised to have a good day at the office, a defensive error undoes all their good work. Similarly, it was Shkodran Mustafi’s horrible mistake which allowed Tottenham Hotspur to steal a point from the North London derby.

Just when it seemed Arsenal would nick the game, Mustafi - who only has a Transfermarkt rating of £27m these days - blatantly brought down Harry Kane, conceding a penalty. This isn’t the first time he’s cost Arsenal a win. Indeed, he’s cost the Gunners crucial points time and again with his erroneous nature, making silly fouls or defensive lapses to allow their opposition to get goals in.

Be it his rash nature or tendency to switch off defensively, Mustafi ends up creating problems for his defensive partners with his lapses in judgements. Just when things look to be improving for Arsenal’s defensive structure, he ends up breaking that rhythm with errors similar to those in league two.

While both Arsene Wenger and now Emery have shown faith in the 26-year-old defender, due to his aerial prowess and strong-tackling, he needs to realize Mustafi causes more problems than he solves for the Gunners.

Even playing him at right-back was ineffective, as he provided nothing going forward and allowed Danny Rose to get past him multiple times. He’s too shaky to hold his own against mobile attacks and should be upgraded upon quickly if Arsenal desire to form an impenetrable defensive line soon.