Ozan Kabak was on the receiving end of a barrage of criticism on Tuesday night following Liverpool's 3-1 defeat against Real Madrid in the Champions League. 

The 21-year-old started alongside Nat Phillips to form an increasingly familiar defensive partnership.

Both players are inexperienced at the top level but have shown promising signs alongside one another in recent weeks. 

Jurgen Klopp has been forced to trust in the pairing amid Liverpool's injury crisis in central defence, and for the most part they have been dependable.

However, their lack of experience on the big stage showed on Tuesday night against one of the best outfits in world football. 

Vinicius Junior's opener, for example, arrived from a straight ball over the top from Toni Kroos.

Take nothing away from the quality of the assist, but it was impossible to escape the feeling that a more accomplished centre-back pairing would have dealt with the initial ball over the top. 

But there was something more particular about Kabak's display that drew merciless criticism from the Liverpool fans on Twitter: his sprint speed and technique. 

The Schalke loanee stands at just over 6ft 1 tall and doesn't appear to be the most mobile of players - that much has been evident since he arrived at Anfield.

And one particular clip of him running back from the Real Madrid penalty area to prevent a counter attack certainly made him look like more of a rugby scrum half than a professional footballer. 

His struggle to cover ground and his markedly rigid technique were criticised during and after the quarter-final clash.

All eyes are on Kabak's form ahead of a potential summer swoop.

The 10-cap Turkey international is on loan at Anfield until the end of the season and both the club's decision makers and the supporters will be actively trying to decide whether he's worth signing him on a permanent basis. 

It's a decision that is unlikely to boil down to the limitations of his sprint speed, but in the modern game a lack of pace can leave defenders incredibly exposed. 

And, in fairness to Kabak, he was clearly busting a gut to get back into position following the corner. 

Fans may doubt his athleticism, but they can't question his commitment on this evidence.