The first-half was marred by a serious injury for Gunners forward Danny Welbeck, who seemed to break his ankle in a challenge as his teammates looked on in horror.
Arsenal fans have now been reacting to the result on Twitter, with many singling out Mkhitaryan for criticism after his performance in attack.
This is Futbol have rounded up some of the best tweets below.
These Arsenal fans seem pretty unimpressed with Mkhitaryan’s display against Sporting, and it is easy to see why. The Armenia international was totally ineffective all day for the Gunners, and was rightly hauled from the action in the second half by manager Unai Emery. It was a performance synonymous with Mkhitaryan’s season so far, with the former Manchester United ace unable to hit the heights of his previous form for the Gunners. There have been some moments of brilliance from the 29-year-old at times, but far too often he has been a passenger for Arsenal, and quite frankly he does not deserve to start at the moment. His limited game time this season in the Premier League is therefore justified, and soon he won’t even warrant a game in the Europa League either. He needs to step up his game or he may even find himself out the door at the Emirates, as many of these fans seem to want to happen.
Mkhi should be sold. He doesn’t look happy. Not creating much either.
— Thomas Shelby (@inchleyroad) November 8, 2018
Mkhi actually gets paid 200k this club is mental
— t ???????? (@VintageRambo) November 8, 2018
Thing is with Mkhi, he's low on confidence, but when he tries something to get his confidence back, he fails.
— Sam (@TheEmeryEra) November 8, 2018
We need to sell Mkhi in the summer and invest in a proper winger.
— Etienne (@etienne_smith23) November 8, 2018
Ramsey, Mkhi been abysmal yet again. Iwobi hasn't seen too much of the ball. ESR and Gwen playing well but serious lack of creativity right now. #AFC
— No clean sheets FC (@sull_noronha) November 8, 2018
Mkhi stinking up the joint as usual
— p (@PEA14SZN) November 8, 2018
Mkhitaryan is a bum
— Kingsley™ (@PartickKingsley) November 8, 2018
How is Mkhitaryan still paid?
— Adnan (@Berndtastic) November 8, 2018
Mkhitaryan isn't good enough for Arsenal Football Club. End of.
— Jamie (@J4m_n3ll) November 8, 2018