Lebanon simply had no answer to the pace, power and skill of their opponents, and were hit by a hat-trick from new Arsenal signing Park Chu-Young.
It was a good night for Premier League players as Sunderland's Ji Dong-won also scored a brace to give Korea an early lead at the top of Group B in the third round of Asian qualifying.
The Korea Republic look good for an eighth successive World Cup in Brazil, and their rampage started as the Arsenal new boy scored with a volley in the eight minute.
Their fans in the Goyang Stadium continued to crave for more goals, and Park obliged by heading in a Ki Sung-yeung corner at the stroke of half-time.
Strikes from Ji, Park, and Kim Jung-woo completed the rout in the second half.