Vastić's first appearance at a major tournament with Austria was at the 1998 FIFA World Cup finals in France, where he appeared in all of the team's three group matches and scored a last-minute equaliser in their second match at the tournament, a 1–1 draw against Chile.
Vastić's initial appearance at a major tournament with Austria was during the 1998 FIFA World Cup finals in France. He participated in all three group matches and scored an equalizing goal in their second match of the competition, resulting in a 1–1 draw against Chile.