​Oh Shkodran. Just where to begin? Just when you thought the German couldn't fall any further in the eyes of Arsenal fans, the centre-back proceeded to tell everyone to hold his drink and watch him do worse.

It may have been a poor team performance from the Gunners, but in clawing themselves back to 1-1 straight after half-time against Crystal Palace on Sunday afternoon, you sensed the tides had turned. The Emirates was rocking, the players smelled blood, and the three points that they so desperately needed were in sight once again.

Wilfried Zaha,Shkodran Mustafi

But in ushering Wilfried Zaha through to score for a nice Easter Sunday gift, Mustafi may have single-handedly cost Arsenal Champions League football next year in the blink of an eye. With the Red Devils getting humiliated at Everton, here was the opportunity for Unai Emery's side to pull away from Manchester United in the race for the top four. 

Instead, the defeat now means everything looks as close as its ever been, and in truth, with three away fixtures still to come, the Gunners are no longer favourites to secure Champions League football next season.

After the game, Emery was understandably protective of his player. Pressed on Mustafi's performances this season, the Spaniard leapt to the German's defence and hailed him as being 'consistent'. The ex-PSG boss was undoubtedly keen to deflect criticism away from the centre-back, but you just wonder whether a Jose Mourinho-style public rollicking might have been the wake-up call needed instead.

In the modern era, the Gunners have had some of the best ​Premier League defenders in the game; the likes of Tony Adams, Sol Campbell, Kolo Toure, Laurent Koscielny et al. But they've had their fair share of the bad too. Igor Stepanovs anyone? Indeed, it was so typically 'Mustafi' that a week after producing arguably his best performance in an Arsenal shirt in a hard-fought 1-0 win at Watford, he proceeded to throw it all away with a piece of mindless defending.

What frustrates and infuriates in equal measure about the World Cup winner (yes, that's right), is the 27-year-old's tendency to repeat the same mistakes. Einstein's definition of insanity was trying the same thing and expecting different results, and in the former Valencia man's case, it's throwing himself into tackles when there's absolutely no need for it. It's reckless at best, and sheer stupidity at worst.

There have been countless moments since his arrival from the Mestalla where just basic communication and understanding of his fellow defenders and goalkeeper would have helped him no end. The Zaha calamity on Sunday was eerily similar to his mistake in Southampton's opening goal at the Emirates last season, when he appeared to just let Charlie Austin ghost in in front of him and steer the ball past Petr Cech at the near post. 

The likes of Stepanovs, Pascal Cygan and Phillipe Senderos all had their moments, but their defensive troubles were somewhat covered up by the rest of the team. In Mustafi's case, any mistake gets amplified, with the Gunners simply not of the requisite quality to make up for it.

A propensity to volley criticism at his teammates, as he did so at Bernd Leno's expense at the weekend, makes it even more impossible for fans to forgive him; in a time when Emery needs his players to embrace the responsibility, Mustafi shirks it. 

Injuries and suspensions have no doubt taken its toll on Emery's selection plans, but it won't be a day too soon if Shkodran Mustafi never puts on an Arsenal shirt again. Extreme measures perhaps, but put simply, Gunners fans at this point would rather have a Didier Drogba-scarred Senderos at centre-back ahead of the bundling German. And that just sums it all up.