Barcelona manager Hansi Flick has raised concerns over the playing surface at the Metropolitano Stadium, casting a shadow over the build-up to Tuesday's pivotal Champions League quarter-final second leg against Atletico Madrid.

Fresh off the plane in the Spanish capital, Barcelona's training session was dominated by Flick's visible frustration. Video footage captured the coach gesturing to UEFA officials and pointing emphatically at areas of the turf, highlighting what he perceives as subpar conditions.

This is not a new issue for Atletico's home ground. Club captain Koke publicly acknowledged the poor state of the pitch back in February, and Flick had already warned his squad about the surface ahead of their La Liga visit earlier this month. With a spot in the semi-finals on the line, the condition of the grass becomes a critical tactical factor, potentially disrupting Barcelona's preferred possession-based style.

The last thing this fiery rivalry needs is another external controversy. Recent clashes have been drama-filled, and the hope is that the pitch does not become a decisive player in the outcome. Barcelona, trailing 2-0 from the first leg at Camp Nou, face a monumental task to overturn the deficit. They will be hoping for a true footballing battle, not a struggle against the elements of the stadium itself.