Barcelona went into the match knowing defeat would hand Real Madrid the title but first half goals from Lionel Messi and Seydou Keita, and an own-goal by Rober, put Pep Guardiola’s men 3-0 ahead at the break, while second half goals from Thiago, Messi and a Pedro double completed the rout.
Pep Guardiola made six changes to the side which got knocked out of the Champions League by Chelsea and the visitors were fortunate not to concede an early penalty when Rayo’s Diego Da Silva Costa was brought down in the box.
Guardiola’s men soon found their feet, however, and made short work of dissecting the Rayo Vallecano defence for the opener, with Alexis Sanchez twisting and turning on the edge of the box, slipping a pass wide to Pedro, who put the ball on a plate for Messi to tap home at the back post.
Rayo looked to hit back instantly and Costa forced a smart save from stand-in keeper Jose Manuel Pinto with a flicked header, before Pulido denied Alexis at the other end with a well-timed sliding challenge.
Barcelona doubled their lead when Alexis broke through the middle, rounded the keeper and squared the ball across the face of goal, with Rober sliding in with an attempted clearance but inadvertently putting the ball into his own net.
Messi was then inches away from adding another, throwing himself at the ball in attempt to meet Pedro’s low cross, while Pinto produced a second excellent save to keep out Roberto Tashorras’ free-kick as Rayo threatened to get on the score sheet.
The away side made it three when Messi cut in from the right, beat two men and slid a beautifully weighted pass to Keita, who made no mistake in beating David Cobeno with a low shot.
It took just 60 seconds for Barcelona to extend their lead after the break, with Messi heading Alexis’ cross against the bar, only for Pedro to smash home the rebound.
Pinto made his third save of the night to keep out Diamanka’s powerful shot, which had the Barcelona keeper, making a rare start in place of Victor Valdes, at full stretch.
Thiago added his name to Barcelona’s ever-growing list of scorers soon after, meeting Dani Alves’ cross with a downward header, before Pedro grabbed his second after being picked out by Messi in the box.
And Messi completed the scoring with a cool finish to take his league tally to 43 goals, tied with Real Madrid’s Cristiano Ronaldo with three games remaining. Real know victory against Athletic Bilbao on May 2 will secure them a 32nd La Liga title.