Mes Kerman had gone into the all-Iran affair brimming with confidence with the club higher in their domestic league than their opponents but their task was made difficult when Abolghasem Dehnavi was sent off in first-half stoppage time.
The visitors, however, made light of their numerical disadvantage and looked to have done enough to send the game to extra time, only for Igor to be left unmarked inside the area following an 84th minute corner, allowing Brazilian striker Igor (Igor José Marigo de Castro) to head home the winner.
The first 15 minutes had been devoid of noteworthy chances, although the impressive Mohammad Khalatbari kept the Mes defence busy with his quick thinking and movement.
Zob Ahan were the first to threaten with quarter of an hour gone when Mohammad Ghazi headed over from a free-kick with just the goalkeeper to beat before Mes had their first chance in the 17th minute when Edinho (Eder Luciano) floated a beautifully weighted free kick into the Zob Ahan box for Gholamabbas Ashoubi, who emerged from a crowd of players to head beyond the stunned keeper, only for the ball to rattle the crossbar.
Those two chances brought the game to life as play swung from one end to another and Mes really should have finished at least three clear-cut chances.
The first of those came after 26 minutes when Edinho received the ball just outside the box and turned towards goal before volleying just wide with his weaker left foot.
Mes again came close in the 37th minute when Mahdi Rajabzadeh dribbled into the area but opted to shoot straight into the keeper’s grateful hands when perhaps a more measured finish would have been the better option.
But Mes' momentum was halted when just before the break Dehnavi was shown his second yellow card after handling the ball.
Consequently, Zob Ahan came out the more confident in the second half and in the 54th minute a fine pass by Sina Ashori into the box for Ghasem Hadadifar allowed the midfielder to turn his defender but his shot was straight into the hands of the keeper.
Khalatbari's trickery once again had defenders left dumbfounded as he worked himself into a one-on-one situation with the keeper, only to send his shot over the bar.
Zob Ahan coach Mansour Ebrahimzadeh opted to introduce Igor in the 80th minute and it proved a wise tactical decision as the forward grabbed the winner four minutes later, heading home from a corner after being left unmarked inside the box.