Zob Ahan upset Al Hilal to reach the final of the AFC Champions League for the first time as Igor Castro netted the only goal of the game at King Fahd International Stadium to seal a 2-0 aggregate victory for the Iranians.
Zob Ahan entered the clash with a slender advantage thanks to Ghassem Hadidafar's strike in the first leg of the semi-final but a star-studded Al Hilal outfit boasted a formidable home record and were unbeaten in Riyadh in this season's competition.
That changed in the 54th minute when Castro capitalised on poor defending from Osama Hawsawi to fire home the goal that booked his side's passage to Tokyo on 13 November, where they will face Korea Republic's Seongnam Ilhwa Chunma.
Lee Young-Pyo was sent off for a needless kick at Mohammad Reza Khalatbari with 20 minutes to go as Al Hilal, who dominated much of the game, were unable to breach a defiant Zob Ahan defence.
"We always trusted that we could reach the final and we always had big confidence. I have been the coach of Zob Ahan for the last three years, the players are like my sons and we all helped each other," said coach Mansour Ebrahimzadeh.
"We had difficult matches, group games against Bunyodkor and Al Ittihad before beating the defending champions Pohang Steelers and tonight, Al Hilal. We controlled the game against Al Hilal and we made sure that time was on our side. We produced a good defensive display and our strikers caused problems for Al Hilal when we managed to keep the ball."
The Iranians nearly opened the scoring in the 20th minute against the run of play when Hadadifar's free-kick penetrated a crowded penalty area but keeper Hasan Al Otaibi did well to push the ball away low at his near post.
Al Hilal's best chance of the half fell to Ahmed Al Fraidi eight minutes later but the midfielder blazed wide from ten yards after Zob Ahan failed to clear Thiago Neves' cross. Christian Wilhelmsson saw a shot following a scramble in the box somehow deflected over the bar by a last-ditch challenge six minutes after the break before Zob Ahan effectively ended the tie three minutes later.
Khalatbari's low cross posed no threat but Hawsawi's weak clearance looped straight up into the air, allowing Castro to bringing the ball down before holding off the defender, swivelling and rifling low past Al Otaibi. Gordan tipped Mirel Radoi's long-range effort around the post at full strength before Al Hilal were reduced to ten men in the 70th minute when Lee booted Khalatbari from behind.
Al Hilal continued to attack right up to the final whistle but Zob Ahan hung on to reach the final. Al Hilal coach Eric Gerets refused to blame skipper Hawsawi for his side's exit.
"We made defensive mistakes and to be honest, we can't just forget that Osama Hawsawi is one of the best players in Saudi Arabia and I would not be fair towards my captain if I were to say he's bad," said the Belgian.
"We played a lot of games where we scored a lot of goals but it was only one game where we didn't manage to defend well. In general, the defenders don't always make mistakes."