Czech Republic's Koubek admits the superior side won after opening loss to South Korea

South Korea came back from a goal down to beat the Czechs 2-1 in Group A, handing Koubek's side their first defeat after a run of six matches without losing.

"We made some mistakes, but we also created chances. Our opponents were very quick," Koubek told reporters. "The better team won."

"We had to battle and we did," he added. "Now we need to move forward. We need to be more attacking and inventive in the final 30 metres. We can improve in attack."

Ladislav Krejci gave the Czechs the lead with a fine header as they dominated in the air, but Hwang In-beom soon levelled and then turned provider for substitute Oh Hyeon-gyu's winner.

Koubek also said the Czechs needed more from key players like striker Patrik Schick and attacking midfielder Pavel Sulc, both of whom he substituted in the second half after they appeared tired in the warm conditions.

The Czechs next face South Africa on June 18.

"We will face a tough opponent, and we have just faced a tough opponent," Koubek said. "It was our duty to play until the end, so it is clear the players are exhausted."

Despite a first loss for the 74-year-old since taking the job, Koubek found positives, especially the midfield performance of Alexandr Sojka, who earned his first competitive cap.

He also played down the travel challenges for the Czechs, who head to Atlanta next week to take on the South Africans while co-hosts and Group A leaders Mexico face South Korea.

"We just have to live with it because that is what others arranged for us," said Koubek. "Our logistics team is good, but it is not ideal that we have to travel that much."