AFC - It was the proverbial 'bad day at the office' for Iran as one of the AFC U-19 Championship favourites were sent packing by a rampant Korea Republic, who eased to a stunning 4-1 win in Sunday's quarter-final.

The Iranians were in impressive form during the group stage but they were a shadow of the side that had scored nine and conceded just one ahead of their last-eight fixture but the Koreans were superior in every department as the East Asians ran out comfortable winners.

"This was the worst day for us...just a bad day," Mohammadi lamented in the posy-match press conference,

"I don't think that the result was because of the difference in the quality of the two sides I think it was largely due to our poor luck. We ran out of luck."

Iran had to chase the match in both the halves with Moon Chang-jin's second minute goal putting the Koreans on top before Alireza Jahan Bakhsh pulled one back for the four-time champions.

The Iranians fell behind for the second time four minutes into the second half when Lee Gwang-hun made it 2-1 and as Iran chased the game they were caught by two late goals on the counterattack through Kim Seung-jun (81st) and Kwon Chang-hoon (90+5) as Korea Republic sealed their place in the semi-finals and their ticket to the 2013 FIFA U-20 World Cup.

"We conceded two early goals in both halves and if you ask me, they were both avoidable goals," continued Mohammadi.

"My defenders did not have a great time due to the physical approach of the Koreans. They are just 18-year old kids so sometimes you cannot control them.

"On the top of that, we could have scored more than a couple of goals in the first half and we failed to do that too."

Lee Kwang-jong, the head coach of Korea Republic, hailed his side's attitude and congratulated his young team for making it to the World Cup.

"I must congratulate them for playing superb football today," he said.

"We knew Iran is a team with physical strength and good tactics so we were concentrating more on the defensive game in the first half.

"Our main strength over the Iranians was our speed so once the Iranian defenders started getting tired we relied on our pace and made it relatively easier though it was not an easy match at all.

"The good sign from the match is that in the group stages we were struggling to get goals despite creating a number of chances in all our matches but today it was a different story, the boys scoring goals at will."