The Catalans saw a 12-point advantage over arch-rivals Real Madrid cut to four after failing to win for three successive games.
Barcelona, who are looking to win their first league title since 2006, drew with Real Betis and lost to Espanyol and Atletico Madrid in their last three league games.
"I think the defeats were all part of the process of fighting for the championship," head coach Guardiola was quoted as saying by Barca's official website.
"But I understand we have to end this run quickly, which is why the next games are so important.
"I sense we'll be champions. We are candidates until the end and I firmly believe we will be champions."
Guardiola, 38, took over at Barcelona in the summer following the sacking of Frank Rijkaard.
The two-time European champions put in some entertaining displays under his guidance to occupy the league summit.
Barcelona also qualified for the UEFA Champions League round knockout phase. They drew 1-1 with Lyon at Stade Gerland in the first-leg of the competition's round of 16.