The visitors had to play with 10 men for the best part of the game in Isfahan’s Fooladshahr Stadium after a VAR review convinced referee Vahid Kazemi to show star winger Mahdi Torabi his marching orders for a foul on Mohammad-Mahdi Mohebbi on the half-hour mark.
Summer signing Mahdi Limouchi missed a glorious chance to break the deadlock for the home side late in the first half, only to see his close-range effort cleared by Aref Aqasi’s tackle on the line and come off the post.
With both sides heading for a goalless stalemate in the first half, Hosseinzadeh gave Dragan Skocic’s men a surprise lead in stoppage time, finding the net on the rebound after Sepahan keeper Payam Niazmand’s save on Igor Postonjski’s effort from outside the box.
Tractor held off the host’s desperate push for an equalizer after the break to walk away with a first win against a Big Four opponent – which also includes Persepolis and Esteghlal – in two years and move atop the table with 13 points, thanks to a superior goal difference over Malavan and Sepahan.
On a rain-soaked pitch in Sirous Qayeqran Stadium, Milad Baqeri headed home an 86th-minute winner to help Malavan continue its impressive start to the season with a 1-0 home win against Esteghlal Khuzestan.
Elsewhere, Golgohar and Havadar shared the points in a goalless game in Sirjan, while Iralco defeated Kheybar Khorramabad 1-0, courtesy of Rahman Ja’fari’s sublime finish in the first half, to celebrate a first victory of the campaign.
Hadi Habibinejad’s 93rd-minute strike led newly-promoted Chadormalou to a 1-0 triumph over Moharram Navidkia’s Mes Rafsanjan at home.
Friday’s results came two days after a stoppage-time spot-kick by Hossein Kan’ani had secured a sensational 1-0 win for Persepolis against archrival Esteghlal in Tehran Derby.
Chasing an eighth league crown in nine seasons, Persepolis is fourth in the table with 11 points with a game in hand, while Esteghlal – without a league victory since the opening-day win at Shams Azar – is 11th with five points.
The Tehran-based clubs will be back in AFC Champions League Elite action on Monday.
Persepolis will be looking to bounce back from a first-day loss at Al Ahli Saudi when welcoming Uzbekistan’s Pakhtakor to Shahr-e Qods Stadium, while Javad Nekounam’s Esteghlal will hope to end the domestic woes in an away game against Al Sadd in Doha’s Jassim bin Hamad Stadium.