WATCH: Mats Hummels literally can’t believe that opposition’s tricky winger is only 17 (NSFW)

It takes a lot to fluster the usually unflappable Mats Hummels.

But Odd Ballklubb had the Dortmund back four run ragged during last night's Europa League qualifier in Skien. Thomas Tuchel's side found themselves 3-0 down after just half an hour before coming back to win 4-3 but Hummels couldn't have been more full of praise for Odd's wingers after the game. Rafik Zekhnini was playing left wing for Odd and Hummels was impressed saying he was "fast and really a nice player." https://twitter.com/AshwinJohri/status/634500382639673346 When the post-match interviewer told the German international that Zekhnini was only 17 years of age, Hummels was so stunned that he reverted to an F-Bomb?

"He's really 17 years old?" he asked. "What the f**k?"

Zekhnini was born in 1998 so yes Mats, what the f**k indeed. H/t to 101GreatGoals