The striker, who joined from Molde in 2009, struggled for playing time here instead going out on loan to Blackburn as well as playing in the reserves.
But he appears to be settling in well at Hannover and in their win over Stuttgart at the weekend opened his account at his new club with a header to make it 2-0.
The game also saw former United reserve keeper Ron Robert Zieler between the sticks for Hannover.
Hannover would go on to win the game 4-2.
Good luck to Diouf at his new club!