Mosquera endured a difficult end to Arsenal's Champions League final defeat to Paris Saint-Germain. The defender was involved in a high-profile incident with Khvicha Kvaratskhelia. The PSG winger beat Mosquera inside the penalty area, prompting the Spaniard to attempt a recovery challenge. Instead, he brought down the Georgian and conceded a penalty.
Ousmane Dembele converted from the spot to cancel out Kai Havertz's early goal, with the incident proving one of the defining moments of the final. The match eventually went to penalties after the score remained 1-1 after 120 minutes. The Gunners lost 4-3 in the shootout after Eberechi Eze and Gabriel Magalhaes both failed to score.

