Blazavic was present in Zurich to watch the draw as Bosnia-Herzegovina were quickly paired off with the Euro 2004 finalists.
"I think that the Portuguese are the favourites to win this tie. However, it's a known fact that the favourites do not always come out winners," Blazevic told reporters after the draw.
"Portugal are a great team and they have a number of excellent players. Nevertheless, I feel like we have what it takes to beat them. We can qualify for South Africa."
Bosnia-Herzegovina travel to Portugal on November 14 and will host Carlos Queiroz's men on November 18 in the second leg.
The play-off surprise package reached this stage by beating Turkey and Belgium to become the runner-up in Group 5 of the European World Cup section.