David Villa opened the scoring in the 20th minute with a cool finish, but despite intermittent threat from the home side, Lionel Messi surged Barcelona further ahead with a thumping effort three minutes into the second half - his 300th senior goal for club and country.

Xavi ended the game as a contest when he struck his 50th La Liga goal in the 79th minute before Cesc Fabregas added the visitors' fourth goal almost immediately after.

And Messi sealed matters with his second a minute before time; taking his tally to 17 in 14 competitive Barcelona matches this season and 73 in all competitions this calendar year.

Barcelona have now won eight of their opening nine games, and sit three points clear of Atletico Madrid, who square off against Osasuna on Sunday, while Rayo remain in 13th place on 10 points.

At the Estadio Benito Villamarin, Real Betis moved fourth temporarily following their 1-0 victory over Valencia.

Valencia, who prevailed in the UEFA Champions League midweek against BATE Borisov, were aiming to end their winless run away from home.

But a ninth-minute goal strike from midfielder Salva Sevilla proved too hot to handle for goalkeeper Diego Alves and condemned Valencia to a fourth away defeat.

Roberto Soldado, who bagged a hat-trick in the 3-0 win over BATE, had a chance during the closing stages to salvage a point for the visitors but he couldn't find a way past Adrian.

Elsewhere on Saturday, Juan Dominguez cancelled out Mario Bermejo's earlier goal as Deportivo La Coruna claimed a point at Celta Vigo, while high-flying Malaga played out a goalless draw with struggling Espanyol.