The former Chelsea and Tottenham Hotspur official praised the BVB man following an impressive performance against his side, and has tipped the 23-year-old for greatness
After his outfit fell 1-0 to Jakub Blaszczykowski's goal, the former Chelsea director stated that Jurgen Klopphas secured a potential world beater, who is capable of taking them to new heights.
"I find Reus a really great player," enthused Arnesen to Bild. "I'm a really big fan of his."
"He is always in motion, so creative, yet manages to score goals. Unfortunately, for what he costs, we would not be able to afford him."
The Germany international teamed up with the Bundesliga champions from Borussia Monchengladbach for a fee of €17.5 million (£13.8m) this summer, and is expected to fill the void left by Japanese playmaker Shinji Kagawa's departure to Manchester United.