Azmoun’s double came in the 32nd and 34th minutes after Nasaf’s Akmal Mosgovoy had struck in the 30th minute to cancel out Mateusao’s 23rd minute opener.
Zoran Marusic was also on target for the visitors on the stroke of halftime in a goal-filled first period.
The win moves Shabab Al Ahli onto 13 points from their six games and confirms Paulo Sousa’s side as winner of the group while Nasaf finish bottom of the standings on four points and is eliminated.