How about Great Moravia surviving? At its maximum extent under Svatopluk I, it inluded (at least according to some accounts) not only what are now the Czech Republic and Slovakia but also Lusatia (much more extensive then than it is now), Silesia, part of Galicia, eastern Austria, Hungary (or rather the area inhabited by the Pannonian Slavs before the arrival of the Magyars), much of Transylvania, etc.
Admittedly, the obstacles to Great Moravia surviving were formidale:
"By the time of Svatopluk I's death in 894, the Great Moravian state had already begun to weaken. According to the chronicle of Byzantine emperor Constantine Porphyregenet, Svatopluk had warned his three sons upon his deathbed that their continued unity would be essential to the preservation of Great Moravian territory and power. Failure to heed that advice contributed to the rapid demise of Svatopluk's fragile kingdom as fraternal disputes in the face of external threats and weak internal organization left Great Moravia in a vulnerable state. A product of conquests and composed of fairly autonomous Slavic tribes and principalities, Svatopluk's state lacked the centralized authority or administrative structure needed to hold its disparate pieces together without his personal leadership.
"After Svatopluk's eldest son succeeded him as Mojmir II (r. 894-907), a power struggle began between the new king and his younger brother Svatopluk II, ruler of the appanage principality of Nitra. With the support of the East Frankish king Arnulf, Svatopluk II precipitated rebellions against Mojmir II in 895 and then again in 897, when Arnulf sent Frankish troops to help defend Svatopluk ll against his brother's attacks.
"A new threat then emerged in the form of the Magyar tribes, which moved into the Carpathian Basin after attacks by the nomadic Pechenegs forced the Magyars to move westward from their lands near the Black Sea in 895..."
https://books.google.com/books?id=sPbqDSWXK7QC&pg=PA31