Greece forced the postponement of Bosnia-Herzegovina's World Cup qualification party as Martin Skrtel's own goal condemned Slovakia to a 1-0 defeat.
Bosnia's resounding 4-1 victory over Liechtenstein put the Balkan nation on the cusp of a summer appearance in Brazil and only an unfeasible goal swing in the final round of games will deny them automatic qualification.
But a lapse in concentration in Piraeus saw Skrtel beat Slovakian goalkeeper Jan Mucha just before half-time to guarantee Greece three points and at least the play-off place in Group G.
Greece host bottom side Liechtenstein on Tuesday while Bosnia visit Lithuania.
Mucha was tipping a bullet header from Dimitris Salpingidis round his post inside five minutes and the PAOK striker hit the target again just before the hour mark.
Slovakia's goalkeeper dealt well with that effort but a lack of communication with Skrtel in the 44th minute caused embarrassment for the visiting side as the Liverpool man's backpass bobbled into the net.
Greece pushed for a second goal, and one of their own making, following the restart but Mucha blocked Kostas Manolas' header before Skrtel cleared an attempt from Kostas Mitroglou to safety.
Fernando Santos' men would finish the game grateful for Skrtel's early error as they wasted a host of chances to pull clear in the last 20 minutes.
Jose Holebas was guilty of missing from a good position before Alexandros Tziolis steered a firm effort into Mucha's gloves.
Slovakia came to life in the final exchanges but home goalkeeper Orestis Karnezis had managed to stay alert throughout.
Martin Jakubko and Skrtel both headed over the bar before Karnezis snaffled Michal Duris' long-range drive to ride out the late siege.