Black to play and win !

In this position, Mamyedarov with the black pieces uncorked a nice move using a tactical motif against the White king.
Can you guess the key move&theme Black used here ?
Focus is on Chess Tactics and Combinations. Features Grandmaster level games, thematic moves and puzzles to solve. Hints, Solutions and Analysis are provided. Keep your game sharp ! --------------------------- (all material copyrighted)
