Speaking to HTV, Kovac said: "Congratulations to Mexico, for 50 minutes they were better team. That is football: when it comes to equal teams, little details decide it. This time those details were two dead-ball situations.
"Mexico gave us a lot of respect, they didn't play with pressing as usual because they knew about our counter-attacks. In the second half maybe we were physically down, and Mexico were better.
"We gave some joy to the Croatian people, especially after first two matches, but today the opponent was better."
Mexico meet Netherlands in the next round.