Bundesliga outfit Bayer and Premier League side Tottenham Hotspur will face each other in the Champions League Group E at the BayArena in Leverkusen on Tuesday evening.
Son is likely to start the match for Spurs and will be an important player over the course of the 90 minutes.
The South Korea international, who can play as a forward or as a winger, has been in brilliant form so far this season.
The 24-year-old has scored four goals and created 13 chances in five Premier League matches for Spurs so far this campaign.
In two Champions League appearances, Son has scored one goal and created four chances.
Son is a former Bayer player, having featured for the Bundesliga club for two seasons before joining Tottenham in the summer of 2015.
Bender has said that he and his Bayer teammates are aware of the quality that the South Korean possesses.
“We know what an outstanding player he is and all about his technical qualities,” the 27-year-old Germany international midfielder told BT Sport about Son.
“The move has done him good and he’s obviously matured. We know all about his strengths. He’s quick, quick off the mark, and can shoot with either his left or right foot.
“We know that when he played for us. In the box or around the box, he’s always dangerous. Sonny is a real threat.”
Tottenham are second in Champions League Group E at the moment with three points from two matches, while Bayer are third with two points.