But that five-point margin is now a deficit of seven and the champions now have less than half of the league to overhaul their fiercest rivals.
Barca had looked so impressive as it thrashed Malaga 4-0 in the last away fixture in La Liga, with Lionel Messi bagging a brilliant hat trick. That, along with the 2-1 win at Madrid in the Copa del Rey 10 days ago, appeared to have banished the Catalan's away-day blues.
However, Saturday night's goalless game at Villarreal was about as bad as it has been for Guardiola's side this season - and not even Messi could save them from another disappointment on their travels.
That's 13 points dropped now for Barca in the league this term, already two more than in the whole of last season. And if Madrid - who beat Zaragoza 3-1 earlier on Sunday - can match its haul of 49 from the first 19 fixtures, the Catalans will need to win all of their remaining 18 games to claim a fourth successive title. Impossible, surely, even for this spectacular side.
BARCELONA | POINTS DROPPED ON THE ROAD
Madrid shows no signs of letting up and, if anything, gained confidence from its Copa del Rey aggregate defeat to Barca this week, buoyed by a positive performance in a 2-2 tie at Camp Nou.
Even with injuries, coach Jose Mourinho has a larger - albeit imbalanced - squad at his disposal and is arguably less reliant on one player.
That Barca rely on Messi is, of course, no bad thing, but the Argentine's fantastic form has dipped over the last three matches and he missed the chance of the night on Saturday, lobbing just wide with only Diego Lopez to beat in the first half.
Madrid's form may yet dip as well, but Mourinho has never let such an advantage slip from his grasp in the past and it's hard to see that happening now, especially as problems behind the scenes have seemingly been resolved.
So even if he is about to leave, as reports on Sunday suggested, it is likely to be with the title under his arm. For any other scenario to occur, Barca must react right now - and there can be no more points dropped away from home. It's a big ask.
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