Robert Lewandowski netted his 24th Barcelona goal to help the Catalans beat Cadiz 2-0 and restore their eight-point lead at the top of La Liga on Sunday.
Champions Real Madrid's win at Osasuna the day before pulled them closer to Xavi's side, who had one eye on Thursday's Europa League play-off second leg against Manchester United at Old Trafford.
However an inspired Ferran Torres helped Sergi Roberto to break the deadlock and Lewandowski added a second to win the game and leave Cadiz, 17th, two points above the relegation zone.
The visitors had two goals disallowed and made Barcelona uncomfortable at times at Camp Nou but their victory rarely seemed in doubt.