(Reuters) - South Korea coach Hong Myung-bo thought his disjointed defense would suddenly find their feet in the heat of World Cup battle having shipped 11 goals in five games in the build-up.

On Sunday he paid the price for such misplaced faith.

Algeria tore his back four to shreds and goalkeeper Jung Sung-ryong pressed the panic button as the African side recorded a 4-2 victory that put them on the brink of the knockout round for the first time.

After scoring one goal in 28 years at the World Cup, Algeria had three by halftime in Porto Alegre thanks to clinical finishing and comical Korean defending.

Center backs Hong Jeong-ho and Kim Young-gwon have been playing together since their days in junior football but on Sunday it was like they had never been introduced.

Fullbacks Lee Yong and Yoon Suk-young were never in the right place at the right time, while goalkeeper Jung flapped and floundered at every cross.

To call it 'schoolboy defending' does a disservice to schoolboys.

Islam Slimani was allowed to run scot-free between Hong and Kim to put Algeria ahead before Jung misjudged a corner and was beaten to the ball by Rafik Halliche.

Hong and Kim, who played together in Korea's run to the quarter-finals of the 2009 U-20 World Cup, were again at fault for Algeria's third, caught ball-watching while Abdelmoumene Djabou found acres of space in the box to score.

After pulling a goal back in the second half, Korea's defense was breached again, unable to handle the quick passing of Sofiane Feghouli and Yacine Brahimi, who easily put the ball past Jung to restore Algeria's three-goal cushion.

POOR STANDARD

"The defense wasn't what it should have been, our players were not up to standard," Korea's downcast coach Hong conceded after Algeria became the first African team to score four goals in a World Cup game.

"They weren't concentrating and didn't defend well, but we still have one game left and I want my players to recover well."

South Korea must now win that remaining game against Belgium on Thursday to stand any chance of qualifying from Group H. Algeria simply have to avoid defeat by Russia to reach the last 16.

Korea's defeat is the latest setback for the four Asian Football Conference teams in Brazil. Japan, Australia, Iran and Korea have yet to record a win among them.

The warning signs have been there all along for South Korea.

Before arriving in Brazil they lost to Mexico (4-0), the United States (2-0), Tunisia (1-0) and Ghana (4-0). A surprise 2-0 win in Greece was their only consolation.

The manner with which South Korea surrender goals must be particularly galling to coach Hong, an elegant, sure-footed sweeper in his playing days who won 136 caps and captained the Koreans to fourth place at the 2002 World Cup.

After watching his side put four past Korea in Miami just days before the tournament began, Ghana coach Kwesi Appiah said: "If my team had lost by four goals it would maybe help me to look at the mistakes and correct them before the World Cup."

Hong should have taken his advice to heart.