Ku qor sii wadida cutubkan - Kostitsyn wuxuu matalay Belarus si ballaaran heerarka ka hooseeya 18 iyo -20. Wuxuu markii ugu horreysay ku ciyaaray heer caalami 2000 IIHF World U18 Championships isagoo shan iyo toban jir ah, laakiin Belarus waxay ku dhibtoon lahayd qeybta ugu sareysa, iyadoo ku dhameysatay kaalinta ugu dambeysa. Sannadkii xigay, Kostitsyn wuxuu la tartamay kooxda Belarusiya ee ka hooseysa 20 jirka tartankii Hockey-ga barafka ee Junior-ka ee 2001.
Horyaalka ugu sareeya. Kadib sanadkaas, markii uu hoos u dhacay 2001 IIHF World U18 Championships, Kostitsyn wuxuu ku soo laabtay inuu diiwaan geliyo 14 dhibcood oo hormuud u ah tartanka shan ciyaarood oo ka tirsan heerka labaad si uu ugu guuleysto horyaalka Division I.