"We had clear plans for all the possible scenarios of this match, and ultimately, I think the altitude here had a major influence on the match," Hong said.

"I could clearly see that Czechia players were slowing down in the second half, and on the other hand, our players kept pushing and pushing and stayed aggressive in the late minutes."

In addition to training in Utah, Korea Republic chose their base camp in Guadalajara while Czechia are camped in Texas and only traveled to Mexico just before the match.

The European side, however, took the lead against the run of play in the 59th minute through Ladislav Krejci's header as Korea Republic paid the price for a host of missed chances.

Hong, however, was proud that his players remained focused with Hwang equalising in the 67th minute and substitute Oh Hyeon-gyu netting the winner in the 80th.

"Even when we were down 1-0, the players fulfilled their roles really well until the end," Hong said.

"Since this was our first match of the tournament, I figured some of the players would be a little nervous but I asked them to not give up until the final whistle and to play as one. They were successful on both accounts."

Hong, who skippered Korea Republic to their fourth-placed finish on home soil in 2002, achieved another personal milestone as the win was his first as head coach as his stint in the 2014 edition yielded a draw and two defeats.

"Personally, I am really happy with this victory, but this was all created by our players with their hard work and dedication," Hong said. "I can't say enough about how well they played today."

Korea Republic next play Mexico - who defeated South Africa 2-0 in their opener - and victory on Thursday will almost surely confirm progress to the knockout stage.

Photos: FIFA via Getty Images