The Blaugrana star believes that the club are in the "optimal position" to win La Liga, the Champions League and the Copa del Rey and are ready to take advantage of any slips-up
The Catalans suffered a 3-1 defeat to Real Sociedad to fall three points behind in the Primera Division title race to Real Madrid, whom they also play in the Copa del Rey final in April.
However, Madrid face city rivals Atletico Madrid in La Liga on Sunday, which could give Barca, who host Almeria, the opportunity to take advantage of any slips-up, according to the 34-year-old.
"We're annoyed about what happened last Saturday. It was a step backwards and we lost an opportunity," Xavi told reporters on Wednesday.
"Knowing that the two Madrid teams are playing against one another, we can't let ourselves down this weekend because we can recover points. One of the two could lose points and we'll be there waiting.
"All three of us are favourites. We're the defending champions and we're in an optimal position to achieve all three titles. We're going to battle for that and be competitive."
Gerardo Martino's men are also in a commanding position in their Champions League last-16 clash against Manchester City, holding a two-goal cushion heading into the second leg.
"We can't afford to fail any more," Xavi continued. "Now is the moment of truth. We're depending on ourselves in all competitions and that means we're still positive.
"The requirement is for us to win everything. We know how difficult that will be but it's what we'll be trying to do. We're depending on ourselves. That's what matters the most, though we'll have to tread carefully and be prudent."