Two goals in as many minutes midway through the first-half killed the game as a contest as Ivan Rakitic and Messi netted before Diego Llorente saw a straight red card for a high challenge on Rakitic.
Messi completed his hat-trick either side of Manucho’s consolation for Rayo.
Luis Suarez also missed a penalty after Manuel Iturra was also sent-off for the hosts before Arda Turan rounded off the scoring with his first Barca goal.
Barca now lead Atletico Madrid by eight points with Real Madrid a further four points adrift in third with 11 games remaining.
Despite Rayo’s precarious position just above the relegation zone, Barca boss Luis Enrique showed the Madrid side plenty of respect by naming his strongest side bar at full-back where Jeremy Mathieu and Sergi Roberto replaced Jordi Alba and the suspended Dani Alves.
Rayo were unbeaten in their seven league games themselves and forced Barca ‘keeper Claudio Bravo into a smart early save as the Chilean international flew to his right to turn away Adrian Embarba’s drive.
However, Rayo’s high defensive line was offering plenty of encouragement to the European champions and it seemed only a matter of time before Barca took advantage as Carlos made a good save at his near post to deny Messi.
The opener arrived in unusual fashion for Barca, though, as an aimless ball punted into the box was dropped by Carlos and Rakitic was on hand to sweep into an empty net
The visitors’ second two minutes later was straight out of the Barca textbook, though, as a brilliant one-two between Neymar and Messi freed the Argentine to slot home from close range.
Llorente let Rayo’s frustration boil over three minutes before the break when he lunged in studs up on Rakitic and was rightly shown a straight red card.
Messi piled on further punishment for the hosts when he casually rolled the ball home after Suarez had smashed against the post soon after the restart.
Rayo showed some resistence as Manucho nodded home his fourth goal in three game from Bebe’s knockdown.
Yet, the hosts momentum was short-lived as they were reduced to nine men when Iturra chopped down Sergio Busquets inside the area after Neymar’s free-kick had come back off the crossbar.
Messi passed up the chance to seal his hat-trick to help Suarez in his battle with Cristiano Ronaldo to be La Liga’s top scorer.
However, Barca’s awful record from the spot this season continued as Carlos made amends for his earlier error with a fine save.
The five-time World Player of the Year had to wait just three minutes more to get his third of the night as Messi sauntered through on goal before slotting past the advancing Carlos.
And Turan rounded off a perfect evening for Luis Enrique’s men when he headed home from Mathieu’s cross five minutes from time.
AFP
