Bayer Leverkusen kept its bid for European football alive with a dominant win.
Azmoun had scored just one Bundesliga goal going into Matchday 22 - he now has three after finding the back of the net in successive German top-flight matches for the first time in his career.
Hertha remained just one point ahead of the bottom four teams — Stuttgart, Hoffenheim, Schalke and Bochum — all on 19 points.
Leverkusen climbed to ninth.