Union Berlin defender Diogo Leite says they'll be wary of facing Jude Bellingham tonight.
Union Berlin make their Champions League debut at Real Madrid.
Leite told Marca of the in-form Bellingham: " I already know Bellingham from last season in the Bundesliga, when he was at Borussia Dortmund, and he is a player of a very excellent level.
"You watch him play and you realise that he has outstanding qualities. He is already at Real Madrid, but he is a top player.
"We may not be a very pretty team to look at, but we are very effective. We have been showing it in recent years: we do not need to create many chances to score goals. At the back we are compact and barely leave any space and, with the ball, we seek to be vertical and reach the rival goal as quickly as possible.
"We don't feel undervalued. We are debutants in the Champions League, but we have our weapons: we come from being fourth in the Bundesliga and doing a good job in Europe. I feel that we have the quality to do a good job in the Champions League."