Liverpool manager Jurgen Klopp has expressed his concerns about his players' shortcomings in dealing with aerial balls.

The German claims that the weakness was already present in the team when he arrived at Anfield, and it persists to this day.

Regarding Saturday's 2-0 loss at West Ham United, in which both goals came form headers, Klopp admitted his disappointment as he prepares his side for Tuesday night's Capital One Cup semi-final first leg against Stoke City.

"We were passive in this moment and that is never good in football, never good in life" said Klopp, talking about Michail Antonio's opening goal in the defeat to West Ham.

"When Alberto [Moreno] goes down it is a foul but we still had 10 players closer to our goal than the player who scored in the end.

"We have an issue with crosses; before we had an issue with set plays. It is always a ball in the air. As long as the ball is on the ground most of the time we handle it. When the ball is in the air we have some problems with the goals we concede.

"We know this. We have to solve this. We are really serious in our analysis, clear in our words. No excuses. We have to change for sure.

"One of the biggest rules in football is that you have to prevent crosses because when the ball is in the air it is 50-50. That is not a good ratio. We have to do better. Talking is easy, changing is more difficult but nevertheless we have to do it."