Runaway La Liga leaders Barcelona held on to draw 2-2 at Celta Vigo on Tuesday with a much-changed side as they survived having Sergi Roberto sent off late in the second half to preserve their unbeaten league record this season.

Barca lead the standings on 83 points after 33 games, 12 ahead of second-placed Atletico Madrid, who visit Real Sociedad on Thursday, while Real Madrid, a further four points back in third, host Athletic Bilbao on Wednesday.

Ousmane Dembele struck his first goal in the Spanish top flight to give Barca the lead against the run of play in the 36th minute but Celta got a deserved equaliser just before halftime when Jonny Castro struck from close range.

Paco Alcacer restored Barca's lead in the 64th minute but Celta, who had beaten the Catalans 4-3 and 4-1 at home in the previous two seasons, continued to pour forward and caused the visitors' inexperienced defence problems.

Substitute Roberto was given a straight red card in the 71st for halting a surging run from Iago Aspas and the Spain striker levelled in the 82nd minute, bundling the ball in with the help of his arm and scoring his 20th league goal this season.

With the King's Cup final against Sevilla coming up on Saturday, Barca coach Ernesto Valverde made eight changes to the team that beat Valencia at the weekend, leaving out most of his regular starters including Lionel Messi, Luis Suarez, Gerard Pique and captain Andres Iniesta.

Celta dominated the final part of the game despite Messi coming on earlier in the second half, but Barca clung on for the draw, staying on course to become the only team to finish a Liga season without losing.