For the man who led South Korea's defense during its journey to the World Cup semifinals in 2002, the performance of the team's backline and goalkeeper against Algeria on Sunday must have been particularly hard to watch.

It seemed all too easy for Algeria, which scored three goals in the first 40 minutes.

"Ultimately, we lacked concentration, and we weren't able to respond to the Algerian attack with intelligence," said Hong Myung-Bo, who was a central defender in four South Korean World Cup squads and is now coach of the national team. "Right from the beginning, it was the defense that crumbled. It was not well organized."

With a squad containing a sprinkling of players with experience in the best European leagues, South Korea has progressed past the group stage in two of the last three World Cups, reaching the semifinals as co-host in 2002 and the last 16 in 2010. The 4-2 loss Sunday means further progress this time looks unlikely from Group H.

Having drawn its opening match against Russia 1-1, the team must beat Belgium handily in its last game, and hope the result of Algeria-Russia also goes its way.

Algeria took the lead after striker Islam Slimani was able to collect a long ball and run unchallenged into the area. Two minutes later, keeper Jung Sung-ryong left his line to meet a corner but failed to collect, allowing Rafik Halliche a free header on goal.

On 38 minutes, another long ball was met by Slimani on the left. He pulled it back to unmarked Abdelmoumene Djabout, who side-footed first time past Jung.

In the second half, Slimani and Yacini Brahimi sliced the defense apart with a quick passing exchange before Algeria notched its fourth.

The defense wasn't the only weak point in the South Korean game. The midfield struggled to keep possession during the first half and was well contained when it sought to move the ball forward. The Korean statistics at halftime were especially damming: not one shot on goal.

After pulling a goal back soon after the interval, Hong took off Park Chu-young, the former star of South Korean football who failed to shine at Arsenal, and replaced him with Kim Shin-wook. But that had little impact on the outcome.

Hong, regarded as one of Asia's greatest players, apologized to the fans in the stadium and took responsibility for the poor showing.

"Everything that we did during our preparation for the match was done on my direction. I think our players did their best until the end," he said. "We still have a match left. We have to bounce back quickly and get ready for that next one."