Barcelona restored their eight-point lead at the top of La Liga thanks to a routine win over struggling Cadiz.
Sergi Roberto gave Barca the lead late in the first half with a rebound after Robert Lewandowski cleared a header off the line.
Three minutes later Lewandowski drilled in a fine drive from the edge of the box after being picked out by Roberto.
It was the first league goal for both players at the Nou Camp since a 4–0 win over Athletic Bilbao on 23 October.
Xavi had chances to extend their lead when Lewandowski hit the crossbar.
The Polish striker has scored 15 goals in his first 19 La Liga appearances – with only Cristiano Ronaldo, in 17 games in 2009-10, reaching that total in fewer matches since the turn of the century.
Barcelona, whose nearest title rivals Real Madrid beat Osasuna 2-0 on Saturday, have won their last seven La Liga games and are unbeaten in 13.
Their remarkable defensive record continues with their 17th clean sheet of a league season, a record after 22 La Liga games (passing Deportivo de la Coruna’s 16 in 1993–94).
Cadiz, who had two Roger goals disallowed, stayed two points above the relegation zone.
