Arash Borhani had cancelled out Stanislav Andreev's superb 28th minute opener in first-half stoppage-time but with the Group B game seemingly heading for a draw following a low-key second-half, Hanif Omranzadeh was sent-off for two bookable offences and from the resulting free-kick, Krimets struck to haul Pakhtakor level with the Iranians on four points.
It was a game that Pakhtakor needed to win and they were first to threaten after two minutes when Esteghlal keeper Mohammad Mohammadi had to tip Sherzodbek Karimov's dipping cross behind.
Pakhtakor boss Ravshan Khaydarov had preferred Nikita Ribkin to usual keeper Temur Juraev and the 19-year-old was called into action after 14 minutes when Kianoush Rahmati stung his palms with a long-range free-kick.
The youngster was involved again six minutes later, palming the ball over the bar after Omranzadeh's long throw had flicked off a Pakhtakor defender before repeating the trick to deny a header from the following corner.
Pakhtakor then took the lead in the 28th minute in stunning fashion. A cross picked out Andreev unmarked on the edge of the box and although his first-time volley hit Pejman Montazeri, the striker displayed exquisite technique to hook the rebound - again on the volley - over his shoulder and in off the far post with Mohammadi reduced to a mere spectator.
Farhad Majidi wasted a chance in the 36th minute when the ball sat up for the midfielder but he fired wide before Amirhossein Sadeghi almost cost Esteghlal a goal two minutes later when he was robbed in possession on the edge of his own box by Dusan Savic but the forward lifted his attempt over the bar.
The visitors drew level in first-half stoppage time when Hawar Mohammed's beautiful flick released Javad Shirzadeh down the left and his cross towards the near post was cleverly guided past Ribkin from close range by Borhani.
The second-half proved a much more mundane affair but Ribkin almost gifted Esteghlal a second in the 53rd minute when he needlessly came charging off his line. Borhani easily eluded the Pakhtakor keeper and only a brilliant block by Akbarjon Ismatullaev saved a certain goal.
A defensive error at the other end then almost let in Savic seven minutes later. Omranzadeh tried to flick the ball away but it came back off the Pakhtakor striker, who bore down on goal, but his shot took a huge deflection off Sadeghi following a fine last-ditch challenge from the defender and looped agonisingly wide.
That proved to be the pinnacle of the action in the second period until Omranzadeh was sent-off with two minutes to go and the Esteghlal defence failed to pick up Krimets at the set-piece, allowing the defender to nod home unmarked from inside the six-yard box.