Defender Akmal Shorakhmedov was the fall guy when he headed Kim Younggwon's vicious cross into his own net just before half-time, but the South Koreans showed enough attacking endeavour to deserve their win at Seoul World Cup Stadium.
The Taeguk Warriors, FIFA World Cup semi-finalists in 2002, open up a three-point lead over Uzbekistan at the top of a tight Group A and will go through if bottom side Lebanon beat third-placed Iran later.
Only the top two teams in Asia's two final qualifying groups win an automatic spot, with the third-placed countries entering a play-off. Group B winners Japan are the only team to book their ticket to Brazil 2014 so far.
After a cagey opening, Anzur Ismailov's long shot forced a save from Korea Republic's Jung Sungryong, and reigning Asian player of the Lee Keunho was guilty of a terrible miss when he sliced an easy shot wide from close range.
Uzbekistan's Ulugbek Bakaev drew Korean keeper Jung into action again with a shot but he also passed up a golden chance when he met Server Djeparov's cross unmarked at the far post, but planted his header high and wide.
Cross brings crucial goal
On 41 minutes, Kim Shinwook's knock-down fell to Lee Myoungju, but Uzbek custodian Ignatiy Nesterov dived low at his feet to deny the debutant midfielder. However, the Korean pressure told just a minute later when Kim Younggwon's arcing cross from deep on the right fell to the unfortunate Shorakhmedov, who could only direct it into his own net.
After the break, Timur Kapadze fired over in a strong spell for the visitors but Korea Republic gradually regained control and had the best chances of the second half. Hamburger SV striker Son Heung-Min beat two defenders with a slalom run into the box but saw his shot deflected, and from the ensuing corner Kwak Taehwi's strong header brought a sharp save from Nesterov.
Kim Shinwook's header was also saved while at the other end the influential Djeparov, a two-time Asian player of the year, came close to levelling it with a run and shot which arrowed wide. The hosts will now await the result of Lebanon's game later against Iran, who travel to Ulsan for their final qualifier next week.
Uzbekistan, still capable of making history as the first Central Asian country to reach the World Cup, are at home to Qatar in their last game next Tuesday.