 Klaassen akaita kutanga kwake kwechikwata chenyika cheDutch padanho revechidiki, achitanga kuDutch U-16 timu musi wa28 Gumiguru 2008 muchikamu chegumi cheTournoi Val de Marne 08 mukukunda 30 pamusoro peItaly U-16, achirova chibodzwa chechipiri cheNetherlands mumusangano wake wekutanga wepasi rose. Klaassen akarova muchikamu chake chechipiri cheNetherlands U-16 mumutambo mumwe chetewo mu 01 kukunda pamusoro peFrance U-16. Pakazara Klaassen akaita 5 kuoneka kweNetherlands U-16 achirova zvibodzwa zvina. Kurova zvimwe zvibodzwa zviviri mumitambo yeushamwari neUkraine U-16 neIreland U-16 futi. Musi wa22 Gunyana 2009, Klaassen akaita mutambo wake wekutanga kuchikwata cheNetherlands U17 mumutambo wehushamwari neFrance U17 iyo yakaguma nekurasikirwa ne1 0 yevaDutch. Musi wa3 Kurume 2010, akarova chibodzwa chake chekutanga kudivi reU-17 mukuonekwa kwake kwechisere, mutambo wehushamwari neGreece U17. Akaitawo basa guru muNetherlands yekugadzirira mushandirapamwe pamberi pe2010 UEFA European Under-17 Nhabvu Championship pamwe nekutamba mu2009 edition yeLa Manga Cup. Musi wa 2 Gunyana 2010, Klaassen akaita mutambo wake wekutanga kuchikwata cheNetherlands U19 mumutambo wehushamwari neGerman U19 iyo yakapera mu 22 dhizaini. Mukuratidzwa kwake kwechinomwe kwechikwata chepasi pemakore gumi nemapfumbamwe, akarova zvibodzwa zvake zvekutanga uye zvechipiri musi wa10 Mbudzi 2011 mumutambo wekukodzera pamberi pe2012 UEFA European Under-19 Championshipvachipesana neMoldova U19 neNetherlands vachikundikana kupinda mumakwikwi ekupedzisira muEstonia. 