South Korea made 13 shots compared to Northern Ireland's four attempts, but it was the hosts who smiled in the end.

"We were on a pitch we had never on played before, so we had some difficulties," he said. "We could have won the game, but the last goal by Northern Ireland ruined it."

South Korea deployed Tottenham Hotspur attacker Son Heung-min as a left winger. The 25-year-old threatened Northern Ireland with his quickness and powerful shots, but failed to score.

"Son was tightly marked and he'll face similar situations in the future," he said. "We have to make Son shine, but he also needs to fight hard to overcome the difficulties."

The match against Northern Ireland was one of two friendlies before South Korea announce their final roster for the 2018 FIFA World Cup in May. The men's national team will face Poland on Tuesday.

Shin said some of the players gave promising performances, mentioning former Borussia Dortmund man Park Joo-ho, who assisted Kwon's goal. Park was playing for South Korea for the first time since June 2017.

"Park played well despite his long absence from the national team," he said. "As for Kwon, he looked little heavy on the pitch, but he'll do well as he plays more games."

Shin had emphasized that the friendly against Northern Ireland was to test South Korea's tactics against Sweden at the 2018 FIFA World Cup. South Korea are in Group F at the World Cup in Russia, along with Germany, Mexico and Sweden.  (Yonhap)