 Despite he scored 20 goals for Dinamo in the 1999–00 season, Niculae was not included by Emerich Ienei in the preliminary squad for UEFA Euro 2000.On 2 September, Niculae scored a brace for Romania U-21 against Lithuania in the first match from the 2002 European Championship qualifiers, counting his first goals in an official match.On 6 October, Niculae played his final match for the U-21 squad, netting Romania's only goal in the 1–1 draw against European Championship holders Italy.