Fresh from contributing to three goals in the 4-1 thrashing of Crystal Palace at the weekend, Monreal continued where he left off against the 'Blues'.
With Arsenal trailing to Eden Hazard's early goal, Monreal was the unlikely source of Arsenal's route back into the game.
Mesut Ozil swung in a corner from the left and the Spaniard rose highest to head goalwards, with the ball taking deflections off both Marcos Alonso and Antonio Rudiger to wrongfoot Willy Caballero and level the scores.
Despite Monreal's contribution, the goal is likely to go down as a Rudiger own-goal.
Check out the strike for yourself below:
24 January 2018