And to add to the fan's pain, Messi is one of her biggest rivals.
The camera pans to the woman's feet to reveal two Real Madrid slippers, would you believe.
The immediate thought that springs to mind is, why was she watching Barcelona?
Is she a Madrid scout, eyeing up the rivals ahead of this weekend's El Clasico?
Or does she support both teams?
Odd.
Nevertheless, we wish the woman well in her recovery. Messi isn't known to have a fierce shot but, as the footage shows, he hit that ball pretty hard.
CHAMPIONS LEAGUE FOCUS
Barcelona went on to surrender a two-goal lead to draw 2-2 against Villarreal but Luis Enrique won't mind too much.
He watched his team extend their lead atop La Liga to nine points and, with eight games remaining, it is only a matter of weeks before Barca lift the trophy.
Barca's main focus - after the El Clasico, of course. Even with an unassailable lead, they will be taking this one extremely seriously - is the Champions League.
The Catalan giants will meet Atletico Madrid in the quarter-finals of the European tournament and Atleti will be fully aware that they pulled the short straw when the draw was made.
WENGER'S WARNING
Barca beat Arsenal 5-1 over two legs despite not exiting third gear and Arsene Wenger's post-match comments were incredibly ominous for any team tasked with stopping Messi, Luis Suarez and Neymar, Barca's fearful front three.
"I think the performance and the quality of our game was good," the Frenchman said, per The Guardian. "I'm disappointed with the result; we played against a team with the best strikers I've seen. The three together are exceptional. They can create chances from nothing.
"As well, Barcelona going forward, the accuracy of their passing, especially Messi, is exceptional. Over 90 minutes he didn't miss one first touch.
"At some point in sport you have to admire art. They have two or three players who transform normal life into art and I respect that. Of course, for me it's suffering but it's exceptional."
All we can say is good luck, Atleti. You better hope Messi's shooting is just as wayward.
