Kim Bo-kyung was South Korea's hero with a second-half winner as they beat Switzerland in their Group B encounter at the City of Coventry Stadium.
Kim, who recently moved from Cerezo Osaka to Championship club Cardiff, volleyed home a deflected cross to move Korea level on four points with group leaders Mexico.
Arsenal's Park Chu-young had opened the scoring for Korea but Switzerland replied instantly through Innocent Emeghara only for Kim to settle the issue.
Switzerland midfielder Pajtim Kasami was booked inside the first 30 seconds after an aerial clash with Ki Sung-yueng.
Korea looked the more threatening in the first half and Park's header was parried away by Swiss keeper Diego Benaglio.
Then an attempted clearance by Fabian Schar struck Park but Benaglio was alert to the situation and able to make the save.
Korea continued to press after the interval and Park finally was rewarded after 58 minutes.
Nam Tae-hee provided an inviting cross from the right flank and Park flung himself full length to head home.
But Switzerland drew level two minutes later with a similar sort of finish from Emeghara.
This time Ricardo Rodriguez supplied the ammunition from the left wing and Emeghara headed past Jung Sung-ryong.
It became three goals in seven minutes when Koo Ja-cheol's centre hit Fabian Frei and dropped into the path of Kim who volleyed into the far corner of the net.