Until the 80th-minute mark it seemed that the Czechs would punish the Koreans' wastefulness, but substitute Oh Hyeon-gyu scored the decisive goal in a Guadalajara stadium that was far from full.

Son Heung-min's Koreans had dominated the first half but were unable to find the net.

The former Tottenham star blasted one effort over the bar before making a driving run to his left and evading two Czech defenders only to shoot wide.

An entertaining second half began with the Czechs scoring against the run of play as Ladislav Krejci rose at the front post to power a header past Korean goalkeeper Kim Seung-gyu.

Hwang In-beom finally made the Korean pressure pay with a clever equalizer as he faked a shot and then caressed the ball over Czech 'keeper Matek Kovar on 67 minutes.

The Czechs had a goal disallowed before Hwang added to his goal with an assist, crossing from the right for Oh to slot home.

When the final whistle sounded after a frantic end to the game, Son sank to the turf in joy.

South Korea face co-hosts Mexico, who beat South Africa 2-0 in the tournament's opening Group A game earlier Thursday, on June 18.

The Czechs play the South Africans in Atlanta on the same day.

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