The prolific Catalans have amassed 47 points from 18 matches this term, scoring 54 goals and conceding a miserly 13, and have a 12-point lead over Real Madrid and Sevilla.
A second-string Barca brushed aside Atletico Madrid to reach the King's Cup quarter-finals on Wednesday, but Guardiola, in his first season in charge, said he and his players could not afford complacency.
"This (team) spirit is the only thing we cannot lose," the former Spain and Barca player told a news conference after the Cup match at the Nou Camp.
"We all feel we have a part to play in every match and every competition and that is a very good sign," he added. "But we know we have to keep going from game to game and not let ourselves relax."
While Barcelona enjoy their good run, champions Real Madrid have been confronting problems off the pitch, with president Ramon Calderon under pressure after the club said it was investigating newspaper allegations of voting irregularities at last month's general assembly.
Calderon has denied any wrongdoing but the accusations have further reduced his standing among fans already unhappy with his failure to make good on pledges to bring in top players such as AC Milan's Kaka and Manchester United's Cristiano Ronaldo.
FULLY FOCUSED
However, midfielder Wesley Sneijder said the players were fully focused on Sunday's match against bottom club Osasuna at the Bernabeu, when they will be looking for a morale-boosting fourth consecutive league victory.
"Our objective is to get the win and cut the gap on the leaders," the Dutch international said on the club's website.
"We still have a great chance to fight for the Champions League and the Primera Liga and those are our goals."
Osasuna coach Jose Antonio Camacho said the Pamplona-based club had picked themselves up after last weekend's frustrating result against Barca, when they led 2-1 with 10 minutes left but conceded two late goals to lose 3-2.
"The team is used to it, it's been like this all year," the former Spain and Real Madrid coach said on the club's website. "The bad thing is having to learn how to lose when you are bottom of the table."
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