Leading 1-0 from the first leg, Zob Ahan travelled to the King Fahd International Stadium knowing the Saudis were yet to lose on home turf in this season’s competition.
Yet they claimed another major scalp as Castro took advantage of Osama Hawsawi’s defensive error early in the second half to stun the hosts – who had Lee Young-pyo sent off 20 minutes from the end – as a fine defensive performance set up a clash with Korean side Seongnam Ilhwa Chunma on November 13 in Tokyo.
"We had difficult matches, group games against Bunyodkor and Al Ittihad before beating the defending champions Pohang Steelers and tonight, Al Hilal," said Ebrahimzadeh (pictured).
"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.
"We controlled the game against 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.
"Everyone loves success and tries to be successful and the target that we had at the start of the season was to reach the final of the AFC Champions League and we managed to do so.
"We had a long trip and we managed through this trip to overcome all the obstacles that we faced."
Ebrahimzadeh will now fly the flag for West Asia when Zob Ahan face Seongnam next month.
"We have a lot of information about Seongnam and we will be ready when we go to Japan,” he added.
“We will study them well and fight for Iran and for West Asia as well and we will try our best to focus on the most important match in the competition."
Al Hilal coach Eric Gerets, meanwhile, refused to lay the blame for his side’s defeat solely at Hawsawi’s door.
"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."
Gerets did admit, however, that Al Hilal have struggled to break down resilient sides like Zob Ahan.
"Our level this season is not the same as last year and I admit that," he added.
"On the other hand, the level last season was very exceptional as we didn't have a period where we lost points or we were weak.
"This year, however, we played games against teams who defend a lot and we had problems scoring but everything has been the same as last year in terms of preparation and training."
Gerets also defended his decision to play Yasser Al Qahtani from the start. The influential striker had been forced off injured in the first leg in Esfahan two weeks ago and failed to make much of an impact as Al Hilal chased the tie.
"We developed a special program for Yasser Al Qahtani in the last couple of days," he said.
"We really wanted him to play and I believed that he was 100 per cent fit and that he had no pain in his ankle, so there was no reason not to put him in the team."