Northern Ireland Under-21s made a losing start to their European Championship qualifying campaign in the Czech Republic on Friday night.
Steve Beaglehole's men had the chance to go ahead in the 50th minute at Stadion Strelnice when they were awarded a penalty, but Everton defender Shane Duffy could not convert the spot-kick.
They were made to pay a heavy price as the hosts took control in the closing stages, as first Marcel Gecov in the 72nd minute, then his Slovan Liberec team-mate Borek Dockal 11 minutes later netted.
Northern Ireland continue their campaign against Iceland in Coleraine on Tuesday.