A lokacin rani na wannan shekarar, Rumawa sun tattara sojoji kuma ba tare da sanarwar yaki ba suka ci gaba zuwa Bulgaria , suna kwashewa da kwashe kauyukan da ke kan hanyarsu.Sarkin sarakuna ya fuskanci Bulgarian a ƙauyen Rusokastro.Ivan Alexander yana da sojoji 8,000 yayin da Rumawa suka kasance 3,000 kawai.An yi shawarwari tsakanin sarakunan biyu amma da gangan sarkin Bulgaria ya tsawaita su saboda yana jiran karin taimako.A daren 17 ga watan Yuli daga karshe suka isa sansaninsa (masandan doki 3,000) sai ya yanke shawarar kai wa Rumawa hari washegari.Andronikos III Palaiologos ba shi da wani zabi illa ya yarda da yakin.An fara yakin ne da karfe shida na safe aka ci gaba da gwabzawa har tsawon sa'o'i uku.Rumawa sun yi ƙoƙarin hana sojojin dawakan Bulgaria kewaye da su, amma abin da suka yi ya ci tura.Sojojin dawakai sun zagaya layin Rumawa na farko, suka bar shi ga sojojin da ke ci gaba da cajin gefen gefensu.Bayan da aka gwabza kazamin fada da Rusokastro ya yi fatali da sojojin Rumawa, suka yi watsi da fagen daga suka fake a Rusokastro.Sojojin Bulgaria sun kewaye katangar kuma da tsakar rana a wannan rana Ivan Alexander ya aika da wakilai don ci gaba da tattaunawar.Bulgarian sun dawo da yankinsu da suka ɓace a Thrace kuma sun ƙarfafa matsayin daularsu.Wannan shi ne babban yaki na karshe tsakanin Bulgeriya da Byzantium yayin da yakinsu na mulkin mallaka na Balkan na karni na 7 ya zo karshe nan ba da jimawa ba, bayan faduwar dauloli biyu karkashin mulkin Ottoman .