Jurgen Klopp has urged Liverpool to be on their guard when their former team-mate Christian Benteke visits with Crystal Palace on Sunday.
Benteke struggled for regular first-team opportunities under the German and was subsequently sold to Palace at the start of this season.
He has 12 Premier League goals in 30 appearances for the Eagles, and Klopp knows the Belgian's aerial threat is something his defensive line will have to manage.
"Crystal Palace are really strong with unbelievable skills in offensive lines. [Wilfried] Zaha, [Andros] Townsend, Christian, [Jason] Puncheon, they are really good footballers," Klopp said in Thursday's media conference.
"When the ball is in the air Christian is a major threat and he is another player with confidence on a good run. If we let them cross 50 balls it's pretty likely he will have some dangerous headers.
"When balls are in the air he's the main threat. He has 14 goals for Palace [in all competitions]. He has confidence and is in a good run. That is one of the best offensive lines in the Premier League. We know how to play against them but nevertheless we have to show it."
Benteke's compatriot Divock Origi has provided much of Liverpool's physical presence up front this season, his performance during Sunday's 1-0 win at West Brom earning particular praise from his manager.
"He had these moments when he kept the ball for us really physically - against the defensive line of West Brom, that's really difficult and that helped us so much," Klopp said.
"Having one or two chances, being involved in two or three more offensive situations, that's what a striker's life is, somehow. You cannot always be only the guy who makes the last touch for an easy goal.
"So that's what I thought was a really big step for him. But we all know he was in shape like this last year around the Everton game, before the Everton game, and then [he was] done with the injury.
"He needed this time to get the level again, but we have to do everything to help him get consistency in this. In this moment, how it looks in training and everything, he's obviously in a good way."