Ballon d’Or winner Cristiano Ronaldo capped a fine week by thrashing in the opening goal at bottom club Real Betis.
Bale, who had last netted against Valladolid on 30 November, curled in a superb free-kick before Karim Benzema scored his 100th goal for Madrid.
Angel Di Maria converted a rebound and Alvaro Morata wrapped up an easy win.
Carlo Ancelotti’s side knew a victory would put pressure on top two Barca and Atletico, who play Levante and Sevilla respectively on Sunday.
And they responded with a dynamic performance against a Betis side who offered little resistance.
Portugal captain Ronaldo, who also scored in Wednesday’s Copa del Rey win at Osasuna, celebrated being named as the world’s best player by blasting in his 21st goal of the season from long range.
Betis keeper Stephan Andersen did not even move and was beaten easily again shortly after by Bale’s pinpoint set-piece.
The Welshman, who moved to the Bernabeu in an £85m world-record transfer, has drawn criticism in recent weeks after failing to hit top form following a calf injury.
And the 24-year-old’s relief was clearly evident as he was mobbed by his team-mates in celebration of his 10th goal for Los Blancos.
France striker Benzema blasted inside the post, following great build-up play from Luka Modric, shortly before half-time to rack up his century in all competitions since joining from Lyon in 2009.
After the break, the away side continued to press and scored their fourth when Argentina winger Di Maria thumped a low drive into the bottom corner.
Substitute Morata, who Ancelotti reiterated on Friday would not be leaving the Bernabeu after being linked with Premier League side Arsenal, clipped in from close range in the final minute.
Betis sacked recently-appointed West Bromwich Albion coach Pep Mel last month and are bottom on 11 points after 20 matches, five adrift of Rayo Vallecano and Real Valladolid.
Written by Steve Milne