Former Real Madrid midfielder Toni Kroos has raised doubts over Barcelona's ability to win the Champions League under Hansi Flick, despite admitting that he loves watching the Catalan side play.

The German, who enjoyed considerable success during his time at the Santiago Bernabeu, believes Barcelona's aggressive defensive approach could leave them vulnerable against Europe's strongest opponents.

However, Kroos was full of praise for Lamine Yamal following the teenager's impressive performance against Atletico Madrid, describing his individual brilliance as something capable of changing a match single-handedly.

Kroos questions Barcelona's Champions League approach

Kroos considers Barcelona one of the strongest teams in European football, alongside Bayern Munich and Paris Saint-Germain, but believes their attacking philosophy could become a problem in the Champions League.

Flick's side regularly commit players forward and operate with a high defensive line, allowing them to dominate possession and create opportunities in the final third.

However, the former Real Madrid midfielder believes that approach can be punished when facing opponents with the quality to exploit the space behind their defence.

“Barca always try to create more chances than their opponents, but in the Champions League, you face teams that can score several goals in a single game,” he said.

Kroos also highlighted how Barcelona can struggle when opponents defend deep and prevent them from playing their usual attacking football.

“You also face opponents who defend exceptionally well and don't let you play your usual game. And in those situations, you must know how to defend yourself,” he added.

He referenced their difficulties against Paris Saint-Germain as an example of the challenges they could encounter against Europe's elite.

Kroos singles out Lamine Yamal for special praise

While Kroos had concerns about Barcelona's overall defensive structure, he was particularly impressed by Yamal's individual performance against Atletico Madrid.

The German highlighted the teenager's ability to create opportunities independently, rather than relying on his teammates to provide him with the ball in dangerous positions.

“Lamine Yamal's first 25 minutes were absolutely exceptional,” Kroos said.

“It was the kind of performance that makes you believe one player can completely change a match on his own.

“Every dangerous Barcelona attack seemed to come through him.

“And it wasn't because his teammates were finding him in perfect positions.

“He was creating those advantages himself, beating opponents and producing chances through his own individual brilliance.”

Kroos even suggested that Yamal's influence was so significant that it was almost as though the winger was demanding possession from his teammates to turn the match around.

The praise highlights the impression the 19-year-old has made, with his ability to beat defenders and create opportunities making him one of Barcelona's most influential attacking players.

Kroos identifies Barcelona's defensive weakness

Despite his admiration for Barcelona's attacking football, Kroos believes their defensive personnel could prevent them from reaching the highest level in Europe.

The former midfielder argued that Flick's system requires defenders who are comfortable defending large spaces and dealing with opposition attackers in one-on-one situations.

He specifically compared Barcelona's options with Bayern Munich defender Dayot Upamecano, suggesting the German international possesses the physical qualities required to protect a high defensive line.

“Barcelona don't have someone like Upamecano, a defender you can leave completely alone in a 1v1 with 30 metres of space behind him and still feel confident he'll handle it,” he explained.

Kroos was particularly complimentary about Pau Cubarsi, identifying the young defender as Barcelona's strongest option at the back.

“For me, Cubarsi is by far their best defender. He has the strength to win individual duels and the speed to deal with difficult situations.”

However, he questioned whether the other defensive options possess the same attributes to consistently protect the space left behind when Barcelona's press is broken.

“The moment an opponent breaks Barcelona's press, there's an enormous amount of space to exploit.

“And the biggest problem is that the defenders covering that space don't have the extraordinary pace or defensive ability required.”

He also mentioned Joao Cancelo and Gerard Martin as examples of players he would have greater concerns about leaving exposed in those situations, contrasting them with Upamecano and Alphonso Davies.

Kroos admits he loves watching Barcelona play

Despite his concerns, Kroos made it clear that his criticism was not directed at Barcelona's overall footballing philosophy.

The former Real Madrid star remains an admirer of the way Flick wants his team to play, particularly their attacking intent and willingness to dominate matches.

“Personally, I absolutely love the way Barcelona play. I think their football is brilliant and incredibly entertaining to watch,” he said.

However, he believes their defensive limitations could ultimately prevent them from turning their attractive style into another Champions League triumph.

“But the problem is that they simply don't have the exceptional defensive quality needed to play that way without exposing themselves to serious problems,” he concluded.

Kroos' assessment therefore presents a clear challenge for Flick. Barcelona have the attacking quality to trouble Europe's biggest sides, but whether their defence can consistently protect the space behind their high line could determine how far they progress in the Champions League.