Madrid: Barcelona have suffered an injury setback ahead of Sunday's crucial La Liga encounter against Real Madrid, with midfielder Dani Olmo sustaining a groin injury during Tuesday night's 4-2 defeat to Paris Saint-Germain (PSG) in the UEFA Champions League.

The 27-year-old was forced off in the first half of the match in Paris and was replaced by Fermin Lopez. The defeat was Barcelona's first of the season.

Although Barcelona's medical staff are yet to complete a full assessment, initial indications suggest that Olmo has injured his left adductor muscle.

The injury is expected to rule him out of Sunday's El Clasico, in which Barcelona could extend their lead over their title rivals to nine points. Olmo could be sidelined for up to a month, potentially missing further La Liga fixtures against Alaves and Atletico Madrid, as well as the Champions League encounter against Aston Villa.

The midfielder is also doubtful for Spain's upcoming UEFA Nations League matches against the Czech Republic and England, scheduled for November 12 and 15, respectively.

Barcelona will be without injured defenders Eric Garcia and Andreas Christensen for Sunday's showdown, while Jules Kounde remains a doubt due to an ankle injury.

PSG hand Barcelona first defeat of the season

Tuesday's defeat proved a major disappointment for Barcelona, as defending champions PSG secured a 4-2 victory at home, with Vitinha and Fabian Ruiz scoring late goals to settle an encounter in which the hosts were twice pegged back.

PSG began aggressively, forcing Barcelona into mistakes near their own penalty area. Khvicha Kvaratskhelia struck the post within the opening two minutes, while Ousmane Dembele and Desire Doue also threatened early on.

Barcelona gradually found their rhythm and created opportunities, but PSG goalkeeper Matvei Safonov denied Raphinha and Gordon in quick succession. Both teams suffered injury setbacks in the first half, with Dembele and Olmo forced to leave the field.

PSG regained control and took the lead in the 38th minute after Barcelona failed to close down Doue outside the penalty area. The forward capitalised on the space to score from distance.

Safonov subsequently denied Fermin's attempt as Barcelona sought an immediate response.

"We were hoping for a win or at least a draw, but now we have to see what the coach tells us we need to improve," Barcelona captain Raphinha said.

The win kept PSG at the top of the Champions League league-phase standings with nine points from three matches. Barcelona, meanwhile, remained fifth with six points after suffering their first defeat of the season. (IANS)