Arsenal's hopes of a top four Premier League finish took a blow on Monday - both on and off the pitch.
Mikel Arteta's slumped to a shock 3-0 defeat away at Crystal Palace, one that allowed rivals Tottenham to keep their spot in the Champions League places ahead of them.
The Gunners do remain level on points with their old foes and have played a game less but now have a serious personnel concern to deal with.
Kieran Tierney missed out at Selhurst Park and it's been claimed the left-back's season is over after picking up a knee problem on Scotland duty.
Arteta admitted afterwards that the injury "doesn't look good".
He said on Sky Sports: "He came back from international duty and felt something wrong in his knee.
"There is some damage there.
"We will hopefully know more on Tuesday but it isn't looking good."
Arsenal were poor in Tierney's absence and his replacement Nuno Tavares particularly so.
The 22-year-old found himself at fault for Palace's second goal before finding himself on the bench for the second-half as Arteta opted to hook him.
And both Tavares' shocker and Arsenal's all-round lifeless performance had Arsenal fans on Twitter lamenting just how important Tierney is to their team.
@Welbeast wrote: "I want to donate my knee to you @kierantierney1"
@ArsenalN7 said: "It's true what they say: 'You don't appreciate what you've got until it's gone’ Arsenal without Kieran Tierney is like a plane that doesn’t fly, our flying Scotsman is the driving force and heartbeat of this young team."
@gunnerblog said: "I am willing to donate my body parts to science to try and save Kieran Tierney."
@afcmase_ said: "Kieran Tierney can have my knee I don’t even need it."
@AFCFahey said: "Now you all know how big a miss Kieran Tierney is. Let your apology be as loud as your disrespect."
@TheShortFuse said: "Are there two worse players for #Arsenal to lose to injury than Kieran Tierney and Thomas Partey? I don't think so."
