Hamburg management are delighted to have completed the signing of Arsenal winger Xavier Amaechi.
HSV have paid €2.5m for the teenager, who has penned a five-year contract.
HSV sports director Jonas Boldt said, "He's a young talented player who has a lot of pace, good short quick moves and one-on-one situations.
"At first I did not think it possible that we could negotiate for this player, but especially Michael Mutzel got in touch with him very early and fought hard for a transfer with the player.
"Amazing was his determination to come to HSV despite many lucrative offers from home and abroad. Even if we expect a lot from him, a little patience is needed."
Amaechi also said, "The conditions at HSV are top. I am really impressed by the team, the fans and the stadium. I think it's a great opportunity for me to play for this club."