Liverpool have signed Uruguay defender Ronald Araujo from Spanish champions Barcelona on a season-long loan, the Premier League club announced on Monday, as they moved to strengthen an injury-ravaged defence.

Ronald Araujo's first-half header gave Barcelona a 1-0 win at home against Rayo Vallecano on Sunday, with goalkeeper Joan Garcia delivering a standout performance to preserve the Catalan side's lead at the top of LaLiga.

Ronald Araujo struck at the death to snatch Barcelona a 2-1 win over Girona on Saturday and lift the champions top of La Liga.

The 25-year-old joined Barcelona in 2018 from Uruguayan side Boston River and has established himself as a core member of Hansi Flick's team.

Barcelona woke up with a familiar sinking feeling on Wednesday, another Champions League hangover, after Paris Saint-Germain thrashed them 4-1 at home to eliminate them in the quarter-finals.

The Spanish champions are languishing in third place in La Liga.

Having suffered a last-gasp defeat by Real Madrid in the Clasico last Saturday despite having the better of the game, Xavi's side inflicted the same suffering on Real Sociedad in San Sebastian.

Barcelona defender Ronald Araujo suffered a thigh injury during the El Clasico victory over Real Madrid, the La Liga leaders said on Monday.