The nation landed the 2010 World Cup, but a disappointing 2014 competition in Brazil saw them fail to make it out of the group stages.
La Roja are seen by the bookmakers as one of the favourites to triumph in Russia this summer, but Real Madrid's Vazquez is not looking too far ahead.
"We have to be realistic: we have a fantastic national team, with some of the top players around, but it's pointless discussing whether we are favourites or not," Vazquez told reporters.
"The only thing we can do is work hard, know where our virtues lie and make sure we arrive in the best possible conditions, after that we can try and win the World Cup."
Spain continued their preparations for the 2018 World Cup with a 1-1 draw against world champions Germany on Friday night.