Lewandowski was left UNABLE TO WALK after taking a knee to the back from Militao

Barcelona striker Robert Lewandowski has revealed he was left 'unable to walk' after a heavy collision with Real Madrid's Eder Militao during El Classico last week.

The Poland national team captain took a knee to the back from the Brazilian defender during Barca's 4-0 loss to Los Blancos in the Copa Del Rey semi-final second leg.

Lewandowski is said to be suffering with back pains as a result of the challenge, which has left his body 'in a bad way'.

The former Bayern Munich forward reportedly asked to be substituted against Real Madrid according to Mundo Deportivo, but continued to play through a 'difficult' second half.

'I knock against Madrid, but I always want to play. In the second half against Madrid it was difficult. I had to ask for the change,' Lewandowski told the Spanish press.

'Yesterday I woke up and couldn't walk, but I tried to play without problems. We work with the physios. It's part of football. I always try to be ready for my teammates.

'The good thing is in the next game I'll be fine. On the field I have to play better, but that kick from Militao left my body in a bad way.'

Lewandowski was deemed fit enough to start for the Catalan giants in their 0-0 draw with Girona in La Liga on Monday evening.

The 34-year-old played through immense pain in Barcelona's most recent league fixture and was unable to walk the following morning.

His performance against Girona drew criticism from fans and experts as table-topping Barcelona dropped points for only the fifth time this season in La Liga.

Lewandowski himself was also critical of his showing in the last two games, citing a need to improve on his recent Barca performances.

'Bobek' claims he will be fit in time to play against Getafe on Sunday afternoon, when he will look to find the net for the first time in three outings.