Essien scored Ghana's third goal

Gyan got the opener in the 35th minute, with Lee Eul-yong levelling in the 49th, catching Ghana goalkeeper Sammy Adjei unawares with a 30-metre strike.

Muntari scored Ghana's second goal three minutes later, heading in a perfect cross, with Chelsea midfielder Essien sealing the win on 80 minutes.

Matthew Amoah also went close for Ghana but fired wide in the 60th minute.

"I am very happy with the build-up, especially because we have scored goals so we can do a good job in the World Cup," said Ghana coach Ratomir Dujkovic.

"We know South Korea are very strong but they didn't push as much as usual.

"Maybe we had more luck in scoring goals but we are strong, honest and have good skill."

South Korea boss Dick Advocaat was concerned by the reverse.

He said: "Attack, midfield, defence, there wasn't a single good point.

"Game by game our team play has been getting worse and that is very disappointing.

"It is quite simple, the World Cup did not start today for us. The World Cup starts on the 13th so wait and see what we will do on the 13th."

The Dutchman's side open their campaign against Togo before playing France and Switzerland.

Ghana, in their first World Cup, face Italy, the United States and the Czech Republic.

Ghana: Kingston (Adjei 46), Pantsil, Pappoe, Mensah, Shilla, Essien, Eric Addo, Appiah, Muntari, Gyan, Amoah (Pimpong 82). Subs Not Used: Otto Addo, Ahmed, Boateng, Dramani, Owu, Quaye, Mohamed, Sarpei, Kuffour, Tachie-Mensah. Booked: Gyan.

Goals: Gyan 35 pen, Muntari 62, Essien 81.

South Korea: Woon-Jae Lee, Jin-Kyu Kim (Sang-Sik Kim 51), Young-Pyo Lee, Young-Chul Kim, Song, Ji-Sung Park, Eul-Yong Lee (Seol 81), Ho Lee, Chu-Young Park (Nam-Il Kim 81), Chun-Soo Lee, Ahn (Jae-Jin Cho 46). Subs Not Used: Yong-Dae Kim, Dong-Jin Kim, Chung, Baek, Won-hee Cho, Do-Heon Kim, Choi, Young-Kwang Kim.