South Korea coach Hong Myung-bo admitted his players were "subpar" in their 4-2 loss to Algeria at the FIFA World Cup.
Algeria blitzed South Korea in Porto Alegre, scoring three goals in the first half before Hong's men hit back after half-time, although they left their run too late.
Hong was frustrated by his side's defensive concentration at the Estadio Beira-Rio as they made it 10 goals shipped in their past four matches.
Islam Slimani gave Algeria the lead in the 26th minute, holding off both Korean central defenders to score and Rafik Halliche doubled the Africans' advantage two minutes later with a free header from a corner.
It was 3-0 in the 38th minute when Abdelmoumene Djabou took advantage of lax marking to score from inside the area, while Yacine Brahimi scored Algeria's fourth just after the hour mark to put his country 4-1 ahead, thanks to a sharp one-two with Sofiane Feghouli.
"The result speaks for itself, we made mistakes today," Hong said.
"We tried to change matters at half-time but since we conceded too many, it was difficult to turn it around.
"Our defence crumbled in the first half, we weren't well organised."
But Hong denied South Korea had underestimated Algeria.
"We knew they were going to be strong opponents," the 45-year-old coach said.
"Today their team was completely different than the one that played against Belgium.
"I think they were very well organised in defence and our players were subpar.
"We still have a game to play, so I want my players to recover quickly in time for it."
Despite the loss, South Korea can still qualify for the knockout stages in Brazil if they defeat Belgium in their final match in Group H.
Belgium have already secured a spot in the round of 16 and if they lost to South Korea, Hong's men could advance on goal difference, as long as Algeria fail to defeat Russia in their final game of the group stage.
|Coach: Myung-Bo Hong|
for Chu-Young Park 57'
for Chung-Yong Lee 64'
for Kook-Young Han 78'
|Bale: I´ll never forget this year|
|Griezmann: I deserve Best Player in Europe Award|
|No surgery for Ayew as West Ham target December return|
|Villarreal did all they could to make it through - Escriba|
|Spalletti rues lack of Roma discipline|
|Conte: Chelsea must learn to kill matches|
|Watford and West Brom crash out of League Cup|
|My longest 90 minutes as a coach - Rodgers|
|AFC Champions League: Goalless draws leave quarter-finals on a knife edge|
|Klopp hopeful over Can injury|
|Champions League play-offs: Nine-man Roma crash out as Monaco edge Villarreal|
|Henderson hails ´outstanding´ Mane after Burton thrashing|
|Chelsea 3 Bristol Rovers 2: Conte´s side survive scare thanks to Batshuayi double|
|Hapoel Be´er Sheva 2 Celtic 0 (4-5 agg): Visitors survive Israeli scare|
|Burton Albion 0 Liverpool 5: Sturridge at the double in Reds rout|
|Leverkusen sign Austria star Dragovic|
|Sakho in the clear as WADA opt against appeal|
|Enyimba 3 Mamelodi Sundowns 1: Udoh brace secures CAF Champions League win|
|Pulisic and Ramos on target as Dortmund wrap up Bundesliga preparations|
|Calleri hoping for Tevez advice|
|Defour hoping for Belgium recall|
|Alaba warns against complacency as Bayern begin Bundesliga defence|
|Bravo arrives in Manchester ahead of City move|
|Dyche backs Gray after striker´s apology for homophobic tweets|
|Gray charged by FA over homophobic tweets|
|Pique: Olympic gold proves Neymar is one of world´s best|
|Marin makes Olympiacos move|
|Zidane arrival the catalyst for one of my best seasons - Ronaldo|
|Moyes ´worried´ about Mannone elbow injury|
|Sidibe rejected Arsenal over playing-time fears|
|Guardiola: Toure could feature against Steaua|
|Hernandez out for two weeks after falling down stairs|
|Bravo nearing City move, admits Guardiola|
|Ballack impressed by Dortmund signings but still backing Bayern|
|Lucescu questions De Boer tactics|
|Milan reject Chelsea bid for Romagnoli|
|Dortmund know how to treat Gotze - Ballack|
|Shevchenko: Bacca must improve consistency|
|´If you heed 100 idiots you will go crazy´ - Bauza on Messi return|
|Valdano relieved over Messi U-turn|
|Nordfeldt in line for loan move after signing fresh Swans deal|
|Dante joins Nice from Wolfsburg|
|De Boer expects fierce fight for Barca number-one spot|
|Newell´s confident over Messi return|
|Stoke confirm Jones interest|
|MLS ´attractive´ to Rooney - Timbers owner|
|Burke re-signs with West Ham|
|Sassuolo rejected Balotelli - CEO|
|Valencia coach Ayestaran rules out Mustafi sale|
|Allardyce plans Guardiola talks over Hart|
|Cahill warns rivals over City attack|
|Allardyce open to Terry England return|
|Drogba dismisses Villa rumours|
|Tuchel pleased despite Dortmund wastefulness|
|Stam´s Reading sign Manchester United youngster Blackett|
|Champions League place main objective for Rodgers|
|Eintracht Trier 0 Borussia Dortmund 3: Kagawa at the double as Tuchel´s men stroll|
|Escriba urges cool heads in Monaco|
|Cherchesov sets bar high for Russia|
|Tite defends Neymar´s captaincy credentials|
|Ancelotti wowed by fit-again Martinez|
|Spalletti: If Roma players are afraid, I don´t want them|
|Klopp laments Origi´s absent rhythm|
|Barcelona let Neymar stay in Brazil ahead of qualifiers|
|De Jong brothers joins forces at PSV|
|Rudiger returns to training|
|Liverpool transfer talk frustrates Klopp|
|Klopp demands final third improvements|
|Everton loan Galloway to West Brom|
|Manchester United loan Borthwick-Jackson to Wolves|
|Braithwaite to snub Premier League interest to stay at Toulouse|
|Strachan leaves out McCormack, Rhodes|
|Napoli plan to limit media commitments|
|Taarabt eager to make Marseille switch|
|Kruse suffers knee ligament injury|
|Rummenigge expects Ribery to be targeted|
|Delaney: Benteke is not Messi, he needs service|
|Ballack urges patience with Pep over City project|
|James happy at Real Madrid - Zidane|
|Harper backs Phelan for permanent Hull role|
|Flexibility the key for Allardyce|
|Allardyce concerned over Hart situation|
|De Bruyne praises Sterling reaction|
|Cavani vows to improve strike rate|
|Britton signs Swansea extension|
|Higuain motivated by ´fat´ comments|
|Conte perplexed by Costa criticism|
|Drinkwater poised to sign new Leicester contract|
|Bobo completes Sydney move|
|Bilic: You can´t count on Carroll|
|MLS Review: Dempsey´s Sounders sink rivals Timbers|
|Zidane: Important year for Bale|
|Galaxy star Rogers alleges homophobic abuse|
|Vieira: Pogba just needs to be himself|
|Bacca: I made a promise to Milan|
|Angry Handanovic critical of Inter|
|Gameiro: Atletico must win at home|
|Klopp: I´d be an idiot if I made a panic buy|
|Simeone: Draw leaves a bad taste in my mouth|
|Montella: Milan must win back fans|
|Asensio revels in goalscoring LaLiga debut for Madrid|
|Atletico Madrid 1 Alaves 1: Hosts denied in dramatic finale|