JOIN USA 31st minute penalty by forward Abas Atwi proved the difference as the 146th FIFA-ranked side produced a resolute defensive display to hold off their more illustrious opponents.
Fans ran on to the pitch at the Camille Chamoun Sports City stadium at the sound of the final whistle with some Lebanese players in tears after recording their first win over the former Asian champions.
The two sides are locked on 10 points from five matches in Group B of the third round of Asian World Cup qualifiers and both will take one of the 10 places available in the fourth round should Kuwait fail to beat United Arab Emirates in the other pool match later.
South Korea had beaten Lebanon 6-0 at home in September but they struggled to establish their normal high-tempo slick passing on the bumpy, hard pitch with the blustery wind also proving a factor. Without their suspended captain and leading striker Park Chu-young, the Koreans fell behind after five minutes when Ali Al Saadi lashed home an unstoppable drive from six yards after he had blocked his team mate Roda Antar’s shot.
The creative Koo Ja-cheol soon brought the Koreans level from the spot but his clumsy waist-high challenge on Mahmoud El Ali gave away the penalty that resulted in the winning goal. In Bangkok, Brett Holman headed home a late winner to send Australia into the next round of Asia's World Cup qualifying on Tuesday, snatching a 1-0 victory that put Thailand out of contention for the 2014 finals in Brazil.
Holman popped up unmarked in the area in the 76th minute and nodded home a Brett Emerton cross from five metres to see off a Thai side that battled to stay in the competition but paid a heavy price for missed chances.
In another match, North Korea beat Japan 1-0 in a tempestuous qualifier, the result largely academic with the visiting Blue Samurai already through to the final qualifying round for 2014.
Brazil score
Jonas Oliviera scored his first international goals to earn Brazil a 2-0 friendly victory over Egypt, for whom midfielder Ahmed Hassan made a record-equalling 178th international appearance on Monday.
The Valencia forward subdued a 25,000 strong crowd in Doha with simple strikes in the 39th and 59th minutes as Brazil strolled to victory against a limited, but willing Egyptian side playing for the first time under former United States coach Bob Bradley.
Hassan, 36, came on as 73rd minute substitute, putting him level with Saudi Arabia goalkeeper Mohamed Al Deayea.