A late goal from Jan Vertonghen made it three wins out of three for 10-man Belgium, and condemned South Korea to a group stage exit.
The Tottenham defender struck with thirteen minutes to go, slotting home after substitute Divock Origi’s shot was parried.
The onus was on South Korea to attack Marc Wilmots’ side, with the Asian side needing a win to have any chance of progressing to the last 16.
But Hong Myung-bo’s struggled to break down a resilient Belgium, despite Steven Defour’s first half dismissal for a studs-up challenge on Kim Shin-wook.
South Korea’s best chance fell to Son Heung-min who struck the bar just after the half time.
Jan Vertoghen had the final say however, with Belgium setting up a last 16 tie against the USA.