Jan Chramosta struck either side of half-time for the Czech Republic as they took control of UEFA European Under-21 Championship qualifying Group 3 thanks to a home win against Montenegro.
The visitors could have leapfrogged the Czechs at the top of the section with victory in Jablonec, but, despite a 75th-minute goal from Asmir Kajević, came up short.
With the leadership of the group at stake both sides began cautiously, but it was Jakub Dovalil's side who settled the quicker and on 34 minutes Ladislav Krejčí worked his magic, allowing Chramosta to finish from eight metres.
Montengro responded after the interval yet were dealt a killer blow when the FK Mladá Boleslav forward scored from an almost identical position after good work from Marek Hanousek. Kajević's long-range effort set up a nervous finish but the unbeaten Czech Republic could not be prevented from going three points clear of second-placed Wales with a game in hand.