Pep Guardiola's side were under pressure after Real Madrid's in-form striker Gonzalo Higuain had struck twice to lead them to a 5-1 win at Tenerife in the earlier kick-off.
Real's sixth straight victory briefly sent them a point clear at the top on 59 points from 24 matches before Barca replied by seeing off stubborn Malaga.
The home side's resistance lasted until just before the half-hour mark when defender Marcelo played the ball into space and Argentina striker Higuain arrowed a low shot past goalkeeper Sergio Aragoneses.
Central defender Ezequiel Garay made a rare foray forward to set up Real's second in the 42nd, Higuain timing his run perfectly to sweep his compatriot's centre into the net from the edge of the penalty area.
Higuain's double gave him 16 league goals this season, one short of top marksmen Messi and David Villa of Valencia.
Midfielder Ayoze pulled one back for Tenerife a minute after the break before Brazilian playmaker Kaka restored Real's two-goal advantage two minutes later.
Cristiano Ronaldo netted a penalty, his 13th league goal of the season, with 10 minutes remaining and substitute Raul glanced in Real's fifth in added time.
"Things were working for us virtually the whole time," Real coach Manuel Pellegrini told a news conference. "However, you always need to improve and we're still not the perfect team."
