Barcelona's perfect season hit its first real wall on Tuesday night, as a 4-2 Champions League defeat at the Parc des Princes ended an 11-game winning streak and exposed vulnerabilities that Hansi Flick must now address quickly. The result itself was damaging enough, but the injury to Dani Olmo has made a difficult week significantly worse. The Spaniard, who marked his 100th Barcelona appearance in Paris, suffered a left adductor injury and will miss approximately one month of action, ruling him out of the El Clasico and crucial fixtures against Atletico Madrid, Villarreal, and Aston Villa in European competition.

The timing is brutal. Barcelona sit top of LaLiga with 27 points from nine games, five clear of Atletico Madrid, and Sunday's home clash with Real Madrid presents a chance to extend that lead or see it cut sharply. Mourinho's side arrive with momentum after a 4-1 win over RB Leipzig, while Vinicius Junior is suspended, adding a layer of tactical intrigue to the fixture. Flick must reorganise without Olmo, whose versatility and creativity have been central to the team's fluency this season.

There is also the subplot involving Lamine Yamal, who scored in Paris to equal Kylian Mbappe's record of 13 Champions League goals as a teenager. His form remains one of the few genuine positives from a week that has tested the squad's depth and resilience ahead of their biggest domestic test of the campaign.