Guardiola, whose future as Barca coach beyond the current season remains unclear, predicted the championship would not be decided until the final three or four games.
Barca took full advantage of Real's 1-0 defeat at Athletic Bilbao earlier on Saturday by thrashing Sevilla 4-0 at the Nou Camp.
With just under half the season gone the champions have 46 points from 18 matches to Real's 41.
"You can be sure of one thing - The league will be decided in the last three or four matches," Guardiola, who turns 39 on Monday, said at a news conference.
Barca's lead over Real was "a mere anecdote that doesn't win you any titles," he added.
The former Barca midfielder paid tribute to Argentina forward Lionel Messi, who scored a hat-trick at promoted Tenerife last weekend and twice more on Saturday to take him top of the La Liga scoring chart with 14.
Saturday's strikes were his 100th and 101st for Barca in his 188th appearance, making him at 22 the youngest player to reach the century mark for the club, Barca said on their website.
After netting 38 times in 51 matches in all competitions last season, including the Champions League final victory over Manchester United, Messi already has 21 in 27 this term.
"He has it in his own hands to break all the records possible and he is still ambitious," Guardiola said. "He is an example for future generations in the way he behaves."
