Arsenal academy chief Per Mertesacker was key to Matteo Guendouzi's loan move to Hertha Berlin.

The 21-year-old made the switch from England to Germany on a season-long loan on deadline day in October after falling out of favour with Arsenal boss Mikel Arteta.

Hertha chief Arne Friedrich has revealed that his former Germany international team-mate Mertesacker pointed him in the direction of Guendouzi in the summer.

"He's a fantastic player," Friedrich said. "We spoke to Arsenal before the transfer obviously, and I also spoke to Per Mertesacker, with whom I played in the national team.

"Every day he shows in practice what a good player he is.

"He's so calm. He wants every single ball, even under pressure. He has his own understanding that he wants to win games.

"He has this intrinsic motivation to just show the world how good he is. This is what we need, this is what everybody needs and he is highly confident, which is also very important for our team because our team is still looking for structure.

"We are very, very happy to have him here and he's worth every penny."