As the final whistle blew, Marc Casado collapsed to the ground in obvious pain. Barcelona had just lost their Champions League opener to Monaco 2-1, but the 21-year-old midfielder had given it his all.

Barca made a poor start to the renewed league phase. The optimism at the start of the season after five wins in their first five games in La Liga was somewhat tempered after a dull defeat defined by Eric Garcia’s red card in the 10th minute.

It was the first defeat in official competition for new manager Hansi Flick — against the same opponents who had beaten them 3-0 in Barca’s traditional season-opening Joan Gamper Trophy friendly in early August. Casado’s display was one of the few positives.

The versatile Casado is making the most of the opportunity presented by Barca’s many midfield absences — Marc Bernal, Frenkie de Jong, Gavi and Dani Olmo are all out injured. With Olmo’s setback the latest, the question for Thursday night’s game was how Flick would adapt further. His solution was to start Casado and Garcia, leaving Pedri free further up.

But a poor pass from Marc-André ter Stegen changed everything. Takumi Minamino intercepted his pass to Garcia on the edge of his penalty area. In his split-second reaction, Garcia (who was not playing in his natural position as a central defender) brought down the Japanese international and was shown a red card.

Playing 80 minutes with 10 men was tough for Barca, especially for their midfielders. Pedri had to move back to a deeper position and although he played with intensity, he did not play his best game.

But at times in the second half, it was hard to notice the deficit. One of the keys was Casado. In the face of adversity, he stepped up — and despite his relative inexperience at this level (this was his first Champions League start and only his fourth appearance in the competition), he looked like a veteran.

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He showed character to face a difficult situation and gave everything until the end, looking like a captain, but without the captain’s armband. He took the initiative at the base of the midfield, always offering himself as a passing option to calmly help build possession.

He was the Barca outfielder who made the most touches, with 65. His solid passing and confidence set the pace for his team-mates — along with Lamine Yamal, who he set up for Barca’s goal to make it 1-1. It was another brilliant strike from the 17-year-old that galvanised his team, his first in the Champions League.

It was Casado’s second assist in two games, following his brilliant pass for Pedri in Sunday’s 4-1 win over Girona, but Casado has already convinced Flick of his qualities. Club sources, who asked not to be named to protect their positions, said Flick was immediately won over by his arrival this summer and that he sees in Casado’s profile a player similar to Joshua Kimmich, who the German coached at Bayern Munich.

Flick reacts on the touchline during Thursday’s 2-1 defeat to Monaco (Chris Ricco – UEFA via Getty Images)

Last season, Casado played for Barça’s reserve team, Barcelona Atletic (who play in Spain’s third division), as a defensive midfielder and right back. During pre-season, he played as part of a double pivot with Bernal, but when the new season arrived, Flick opted for just one pivot, with the promising 17-year-old Bernal (who has since suffered an anterior cruciate ligament injury) being selected to start.

Still, Casado is at peace with the fact that the German coach rates him highly. Under Xavi, he did not have that confidence. Before this season, he played only 58 minutes for the first team.

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“We have players who gave more than 100 percent today and Casado was one of them,” Flick said in his post-match press conference. “Yamal and Raphinha did the same. I am proud of this team, but we have to accept how we lost today. We have seven games left (in the Champions League competition phase).”

Casado finished the match limping. Maybe it was from overuse, maybe from a blow in a challenge, or maybe it was just because he was broken.

While his teammates helped him stretch, Flick ran as fast as he could onto the field to see what was wrong when the referee blew the final whistle. He found him lying there with signs of pain and talked to him.

“He’s fine, he just took a hit,” Flick said.

Barcelona were defeated, but Casado came out stronger in this match, while in Barcelona there are more and more critical voices about Ter Stegen. For the first time his performances aroused scepticism among fans who until now saw him as the ideal goalkeeper for Barcelona.

(Top photo: Chris Ricco – UEFA via Getty Images)