Xavi is very confident about his team Barcelona. Because after Xavi joined the team, he strengthened the team tremendously. Xavi added some new players to the team, and subsequently trained the players to great effect, making Barcelona one of the best teams in La Liga at the moment. It will be really sad news for Xavi if Barcelona fail to secure the title despite such a good performance.
I have no reason to doubt Barcelona in the next 5 matches to secure the title. Barcelona only need 1 win from their remaining 5 matches to seal the title, so I don't think it's unreasonable to expect them to fail to do so. This season is a perfect season for Barcelona in La Liga, not only are they going to win the title, but they have developed into the team with the strongest defense in the world today than any team in any domestic league.
While I have forgotten La Liga this season for Real Madrid since Barcelona leads the standings with a points advantage. I don't believe Barcelona can be that strong in La Liga, but either way I think they deserve respect for their top performances although I'm Real Madrid fan.