Vlaović was a member of the Croatian squad that surprisingly won the bronze medal
at the 1998 FIFA World Cup finals in France,
their first FIFA World Cup appearance.
He appeared in all of Croatia's seven matches at the tournament,
although only making one appearance over the entire 90 minutes in the semi-finals against France.
In the 80th minute of the quarter-finals against highly favoured Germany,
he scored the second goal in Croatia's 3-0 victory, which all but secured the team's place in the semi-finals.