South Korea's senior national football team players said Monday they believe the young Taeguk Warriors will make further progress at the FIFA U-20 World Cup.

Hosts South Korea in the 24-team FIFA competition will play their round of 16 match against Portugal on Tuesday at the 25,814-capacity Cheonan Sports Complex in Cheonan, some 90 kilometers south of Seoul. They have qualified as Group A's runners-up behind England with two wins and one loss.

While under-20 players are busy preparing for their knockout match, senior national team players also gathered at the National Football Center in Paju, north of Seoul, to train for their crucial 2018 FIFA World Cup Asian qualifier against Qatar next month.

With only three matches remaining, South Korea are currently in second place in Group A of the final Asian qualifying round with 13 points, four behind Iran and one ahead of Uzbekistan. Only the top two teams will earn automatic berths to the World Cup.

Captain Ki Sung-yueng said he doesn't have big concerns for the U-20 side. The Swansea City midfielder previously played at the 2007 U-20 World Cup in Canada.

"Since many people give their support to the U-20 team, I'm sure young players will get more energy," Ki said. "I'm proud of young players for handling the pressure, and I hope they go as far as they can for the sake of South Korean football."

Tottenham Hotspur winger Son Heung-min said the U-20 players should play with confidence, but they should not be too excited about their own performance if they want to become better players.

"In order to keep up their good form, I think they should not be cocky and maintain their humble mindset and fighting spirit until the end," he said. "All the players are talented and if they do well, we'll have a bright future in South Korean football."

When asked about whether South Korean U-20 forward Lee Seung-woo, who has bagged two goals so far while showing dazzling dribbling skills, is his successor, Son said he is not in position to judge the FC Barcelona prospect.

"I don't even know what I'm going to be next," he said.

"Although I haven't seen many of their matches, they've really played well."

Son predicted South Korea will overcome Portugal and clinch a spot in the quarterfinals, but boosting their morale is important.

In the U-20 World Cup, South Korea could have clinched the top spot in Group A, but lost 1-0 to England and settled for second.

"I wanted to visit the stadium, but I heard that tickets are sold out," he said. "If the U-20 side can perform the way they've been playing, I believe they will reach the quarters."

FC Augsburg midfielder Koo Ja-cheol said he has no doubt that the young footballers will play a good game against two-time tournament champions Portugal. Koo wasn't selected to the 24-team senior team squad for the World Cup qualifier due to a knee injury, but he was at the NFC to support his teammates.

"South Korean football is currently in the transition period after the 2002 World Cup," he said. "But it feels good that we're seeing good players like Lee Seung-woo and Paik Seung-ho."

Koo represented South Korea in all age groups, having competed at the 2009 U-20 World Cup, the 2012 London Olympics (U-23), and the 2014 FIFA World Cup. He hopes many young players will grow through the U-20 World Cup at home.

"I'm sure they are getting a lot of attention from fans right now, but I want the players to get rid of negative thoughts," he said. "Although I don't know much about Portugal, I believe we can win." (Yonhap)