The Gunners finished fifth in the Premier League in Unai Emery's debut term in charge and have performed well in Europe to reach the final. Even so, throughout the campaign there have been defensive issues for Arsenal, with Mustafi himself often culpable for opposition goals.
Speaking ahead of Wednesday's game, the centre-back has defended the way in which the back line has performed, per Nick Miller of ESPN FC:
"If you make 90 per cent of your job and in the 10 per cent the opponent scores a goal, people forget about the 90 per cent. If in the end of the season you made 70 points it is for a reason. I don't think that if the defence is not doing our job you would make 70 points.
"If a striker misses a goal or a penalty or whatever, you get a new opportunity five or 10 minutes later. For us defenders, if you make one mistake and they score, even if in five minutes you save something on the line, people still won't talk about it. You get to live with it because it is part of our job."
There were times throughout the campaign when the team crumbled at the back, and Mustafi has been a liability on occasion. James Benge of Football.London doesn't think the German has enjoyed a positive season:
While Mustafi has underwhelmed since arriving from Valencia, Arsenal's defensive vulnerability is a collective problem.
Squawka Football noted how rash the Arsenal defence has been during 2018-19:
Not only does the team appear to lack cohesion at the back, often they are poorly protected by the midfielders ahead of them. Supporters will be hoping the Gunners invest in defensive positions during the summer.
If Arsenal can find a way of bringing the quality of their defence closer to the standards of their attack, they'll be much more of a force next term. BT Sport reflected on some of the fine work from Alexandre Lacazette and Pierre-Emerick Aubameyang in attack:
Should Arsenal win on Wednesday and secure UEFA Champions League football for next term, they will need to defend well. In Eden Hazard, Chelsea have a world-class forward to call on, and if there are any lapses at the back for the Gunners, he'll exploit them.
After his comments, there will be an extra focus on Mustafi should he be included in the XI. Arsenal fans will want to see him end a season of disappointment on a high.