The midfielder feels that the Catalan giants must continue their good start to the season and that it hasn't been spoiled by their draw with Los Blancos
The Spain international has been instrumental in Tito Vilanova's team's ascent to the top of the league, and he reassured fans that they are still in pole position to regain the title after their 2-2 draw at Camp Nou.
"It was a shame because we had a great opportunity to lead them by 11 points at this stage, which would have been impressive, but it's still a good eight-point lead and we have to seize [the opportunity]," he told Mundo Deportivo.
"We started the league very well, but much remains. [The Clasico] was a great match, a great match.
"In the end, looking at the table, it was not a bad result, but we always like to win and we have that taste of losing the opportunity we had."
After Pep Guardiola stepped down as Barcelona coach at the end of last season, his assistant Vilanova was named as his successor, and Xavi believes the pair share similar footballing beliefs.
"They are almost the same but have different personalities. This is normal," he explained.
"When switching from coach to coach people wonder what the differences are, but the philosophy has not been touched. Tito has spent four years with us and Pep and the philosophy is the same."
The five-time Ballon d'Or nominee was speaking ahead of Spain's World Cup Qualifier against France on Tuesday, and he feels that a win would be a big step towards World Cup 2014 for the current world and European champions.
"It is the most important match. Normally the next match is always the most important, but with France and seeing the group, they are the strongest rivals on paper.
"It is the key game. If we win, we have a 75 per cent chance to be in the World Cup."