FOZ DO IGUACU, Brazil (Yonhap) ― With the clock ticking down to its first World Cup match in Brazil, South Korea on Thursday concentrated on shoring up its defense.

For nearly two hours on the second day of training at its base camp in Foz do Iguacu, southern Brazil, South Korea head coach Hong Myung-bo put his 23-man squad through a series of drills aimed at gaining an edge in ball possession and applying a forecheck on opposing ball carriers.

Hong divided his outfield players into two groups of 10 in fast-paced, half-field sessions, directing all players, from defensive backs to forwards, to tighten their space among themselves.

Hong had earlier said the three-day period starting Thursday will be the most crucial stretch for South Korea, as his team gets ready to face Russia next Tuesday. Matches against Algeria and Belgium will follow in Group H for the nine-time World Cup participant from Asia.

Afterward, players, regardless of their positions, spoke of the importance of cohesion on the defensive end, especially in light of their 4-0 loss to Ghana in the final tune-up match on Monday in Miami.

“We’ve been trying to work on our organization all along,” said defender Lee Yong, who will likely get a starting nod as a right fullback against Russia. “We have five days left (before facing Russia), and I think we’ve made strides in that regard. If we can bear down mentally, we should have a good result.”

Kim Young-gwon, also a likely starter as a center back, said the key to ensuring cohesion is “communication.”

“We‘re trying to talk to each other as much as we can, so we can solve our problems (with organization),” Kim said. “As defenders, we need to be in constant communication with our teammates in front and try to get everyone on the same page.”

The importance of defense wasn’t lost on two attacking players, Lee Chung-yong and Son Heung-min.

Son, a rising star for Bayer Leverkusen, is being counted on to provide some offensive spark for South Korea. At least during Thursday’s practice, however, the 21-year-old appeared to have put his scoring ambitions on hold in favor of commitment to defense.

“Coach Hong emphasized making the right moves on defense,” Son said. “I think these defensive drills were helpful to me because I learned how to take care of the defensive part of the game.”

When asked if focusing on defense might rob him of opportunities on offense, Son said, “Everyone has to sacrifice for the good of the team.”

Lee kept mum when pressed on specifics of South Korea’s preparation against Russia but said, “We concentrated harder on prepping for Russia than before.”

“We still have some work to do as far as our spacing is concerned, but I think we should get better over time,” he said.

“It‘s also crucial for offensive players to help out on defense.”

Lee and the rest of the team will remain secretive over the next two days. The Korea Football Association announced that only the first 15 minutes of practice on Friday will be open to the media, and that the entire practice on Saturday will be held behind the closed doors. Players will be available for interviews on Friday but not on Saturday.

The team will depart for Cuiaba, the site of the match against Russia about 1,100 kilometers north of Foz do Iguacu, on Sunday.