The 21-year-old South Korean scored on his debut in a 2-1 defeat at the weekend against 1860 Munich, but ended up on the winning side in a comfortable run-out against the Serie A side.
Son joined Bayer from Bundesliga rivals Hamburg following the departure of Andre Schurrle to Chelsea.
In other continental warm-ups, Borussia Monchengladbach defeated fellow Germans Nurnberg 3-0 thanks to Germany U21 star Patrick Herrmann’s brace.
Eredivisie side Twente cruised to a 4-0 win over FC Den Bosch, Toulouse won an exciting match 3-2 against Nimes, Stuttgart were thwarted 2-0 by AA Gent and Werder Bremen were beaten 3-2 by FC Zwolle.
- Sports & Recreation
- Andre Schurrle