Crystal Palace ended Arsenal's 11-game winning run, holding them to a 2-2 draw, and fans were not impressed with Mustafi's clumsy challenge in the box just before halftime.The home team led at Selhurst Park and scored for the first time this season at home. The German's mistimed challenge led to Martin Atkinson's decision to award the spot-kick to the Eagles. Eventually, Luka Milivojevic sent Bernd Leno the wrong way and gave his side the lead.Throughout the first 45 minutes, both teams had their chances. Wilfred Zaha came closest to scoring before the opener, but the woodwork denied him. The Gunners were pretty lucky to just be a goal down at half-time. Arsenal have been known as the second-half team, as the majority of the decisive results came from the second 45 minutes of the game. Although Unai Emery's side did have a couple of chances in the midst of the exciting half, they barely troubled Wayne Hennessey.In the second half, however, Arsenal scored two goals in quick succession, and they seemed on course for victory number twelve. However, another penalty was clumsily given away by Xhaka, and Milivojevic scored from the spot once more to bring Palace on level terms.Next week, the Gunners will host Liverpool at the Emirates, and their defensive fragility could cost them against one of the most fearsome attacks in the world.Arsenal had struggled defensively throughout Arsene Wenger's last few seasons in-charge and Emery clearly has not quite solved the issue at the back. At the same time, the Gunners are now facing a defensive crisis, with both Nacho Monreal and Sead Kolasinac out of the team with hamstring injuries. Here was how Twitter reacted to Mustafi's foolish challenge against Crystal Palace.Had been saying before the game that Mustafi had been in a good spell of form simply because he had cut out those stupid, rash errors of judgement. Just a crazy attempt of a challenge there.— Charles Watts (@charles_watts) October 28, 2018Mustafi in the box.... pic.twitter.com/3w8PREpDZl— Feverpitch (@feverpitch) October 28, 2018🕵️‍♂️ Worlds greatest mysteries...- How Stonehenge got there? - Who was Jack the Ripper?- How did Mustafi win a World Cup? #CRYARS pic.twitter.com/8uWQoGzr9F— The Sportsman (@TheSportsman) October 28, 2018🧠 Mustafi when asked to defend... #CRYARS pic.twitter.com/vittPnQlio— The Sportsman (@TheSportsman) October 28, 2018Another typically indifferent first half, should have been behind earlier. Daft challenge from Mustafi but Mustafi gonna Mustafi. Just have to hope we produce another typically impressive second half.— arseblog (@arseblog) October 28, 2018Mustafi firing shots at Wenger saying Wenger didn’t tell him what to do, mate, you don’t need someone to tell you to don’t two foot an opposition player that is back to goal in your own box. Really lacking some brain cells there.— Spanish Gooner (@elspanishgooner) October 28, 2018Running out of words to describe Mustafi. Useless, useless bloke.— Frankie Hobbs (@Frankie_Hobbs) October 28, 2018He'd been playing really well of late. Really well. But that is completely brainless from Mustafi.— James Benge (@jamesbenge) October 28, 2018Mustafi is a walking accident. Time and time again he makes stupid errors.— Alex Shaw (@AlexShawESPN) October 28, 2018Mustafi stupid tackle. Stay on your feet you fool. 1-0 to Palace— LTArsenal™ (@ltarsenal) October 28, 2018When Mustafi tries to blame someone else for the goal. pic.twitter.com/V0b8rCdhHk— GG3 (@AFCBeef) October 28, 2018Thought Mustafi had played rather well up until that poor challenge for the penalty. But not exactly the first time his mistake has cost Arsenal. #CRYARS— Mattias Karén (@MattiasKaren) October 28, 2018Poor poor decision by Mustafi. This game just got even more difficult, let's hope we step it up now...— Chris Davison (@cdavison_afc) October 28, 2018A 20% fit Koscielny would be better than Mustafi. How is this man playing at Arsenal ffs— Dostoyevsky (@KozielloEN) October 28, 2018Mustafi’s goal celebration is an Eagle, Palace’s crest is an Eagle. Mustafi just gave penalty away to Palace. Coincidence? I don’t think so.— Lacazettes (@Lacazettes) October 28, 2018