Slovakia 3-1 Latvia Jozef Bubenko's team recovered from recent setbacks to win comfortably in Senec.
Bubenko led Greek club Panionios NFC to UEFA Cup qualification last season, and here his methods helped his country's Under-21s to a deserved victory.
Slovakia claimed an early advantage when Milan Ivana, one of three foreign-based players in the team, scored on 13 minutes. That advantage was doubled soon after as Radovan Kulík of FK Dukla Banská Bystrica found the target.
Although the visitors, who threatened sporadically, reduced the deficit with Vladimirs Volkovs' 26th-minute strike, FK AS Trencín forward Ivan Lietava secured the points with a goal three minutes after the restart.