 Chinnapasaen akakwanisa kupinda mumakwikwi evarume e50 m freestyle kumaOlympics ezhizha ra2004 kuAthens, nekunyora nguva yeFINA B-standard yekupinda ye23.20 kubva kuSoutheast Asian GamesmuHanoi, Vietnam. Akadenha vamwe vanoshambira vanomwe mukupisa kwechitanhatu, kubatanidza mukwikwidzi weOlympic katatu Julio Santos wokuEcuador. Akamhanyira kunzvimbo yechitanhatu nechidimbu chezana chechipiri 0.01 shure kweCyprus Chrysanthos Papachrysanthou muna 23.52. Chinnapasaen akakundikana kuenda kuma semifinals, sezvo akaenzana nenzvimbo makumi mana nenhanhatu yekubatana nemenduru yeSEA Games uye aimbove mukwikwidzi Allen Ong wekuMalaysia mumatanho ekutanga. 