Iran, who controlled the proceedings throughout the Group C match, scored through Younes Delfi (6th and 42th), Allahyar Sayyad (49th) and Vahid Namdari (75th) at the Nehru Stadium here.
Nothing went right for the Germans who were disorganised in the midfield and they could not trouble the rival defence. Their defence also kept a lot of space which the Iranians exploited with repeated forays.
Iran, who beat Guinea in their opening match, now sit on top of the group with six points and thus qualified for the round of 16.
Germany, who beat Costa Rica 2-1 in their opening match, now need to win against Guinea in their final group match in order to qualify for the knock-out round. Guinea and Costa who played out a 2-2 draw today have one point each.
Iran, who adopted a defensive approach in their last match, today preferred to play an attacking game and the move paid off as they took the lead in the sixth minute when Younes Delfi took a shot which deflected from rival defender Jan Boller's leg and found the net.
The early goal put the Germans in complete shambles. The Iranians attacked the German citadel regularly and could have increased the lead but keeper Luca twice denied Mohammed Ghobeishavi from scoring.
Luca Plogmann once again had to dive to bring a save from llahyar Sayyad in the 25th minute.
The pressure on the Germans was so much that they conceded another goal in the 42nd minute as Younes Delfi once again scored with a glancing header from a free kick taken by Mohammed Sharifi. The Iranians were 2-0 up at half time.
The Iranian defence gave a good account of themselves and did not allow the Germans any space to operate inside the danger zone.
The Germans had only one chance to score in the dying minutes of the first half when John Yeboah's try went over the bar from close.
After the change of ends, Younes Delfi could have scored a hat-trick but German keeper Luca once again came off to his side's rescue and denied him in the 48th minute when he blocked his shot.
But a minute latter, Delfi made a good move on the right and send a cross into the box which Allahyar Sayyed headed the ball into the net to kill the contest in favour of Iran.
Substitute Saeid Karimi then played a one-to-one pass with Vahid Namdari who shot home from close to complete the rout.
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