Mohammad Ghobeishavi (25') and Taha Shariati (29') scored from the spot in the first half, and Mohammad Sardari made it 3-0 with a late strike as Iran maintained their unbeaten record in the U17 World Cup group stages with a 3-0 win over Costa Rica, which helped them top Group C, going into the knockout stage.
Iran had already qualified for the round of 16 with wins over Guinea and Germany in their first two games.
Germany, who beat Guinea 3-1 at Kochi in the other match of the day, finished second with six points, and will now travel to Delhi to play against Colombia in the knockout round. Iran will stay in Goa to play against one of the third best teams from either Group A, B or F on October 17.
Iran employed five defenders and slowly opened up the rival defence with raids from the flanks as Costa Rica's panicky defence conceded two penalties in a span of four minutes.
Amferny Arias, going for an aerial ball, brought down Younes Delfi inside the box and referee Hamada Nampiandraza awarded the spot kick, which Iran captain Ghobeishavi converted by finding the bottom right corner. Costa Rica conceded a second penalty when defender Karin Arce needlessly pushed down Younes Delfi inside the box. On this occasion, defender Shariati stepped up to make it 2-0.
Iran remained in control throughout, and rounded off the tally through Sardari's strike off a through ball by Airhossein Hosseinzadeh.