Barcelona were held to a 0-0 draw at Huesca but Ernesto Valverde's side, with star players including Lionel Messi and Luis Suarez rested for next week's Champions League game against Manchester United, still moved 12 points clear of Atletico Madrid.
Huesca's Enric Gallego had an early chance, only for his control to let him down when a shooting opportunity looked to open up.
Back came Barcelona, Dembele getting away from a defender on the edge of the area but he was crowded out before he could get a shot in.
<"photo caption="Arturo Vidal admitted that's Barcelona's listless performance on Saturday was partly due to them thinking about Manchester United.">
Kevin-Prince Boateng shot over as Barcelona began to take control, but clear chances were few and far between in the opening half-hour.
Ezequiel Avila was wayward from distance for the home team, and then Moussa Wague's cross from the left narrowly eluded the stretching Boateng.
Gallego fired wide after seizing on a loose ball as the first half ended goalless, with Barcelona a whisker away from breaking the deadlock early in the second when Malcom hit the post.
With 10 minutes remaining, Barcelona brought on Arthur for Alena, but they were unable to break through and survived a late penalty appeal when Chimy Avila went to ground under a Wague challenge.
"Of course we always want to win, but there were some exceptional circumstances for us here," Valverde told his postmatch news conference.
"We'd played Wednesday [against United] and we have the second leg on Tuesday. I thought it was time to make changes. It was a test for the players that played, and I think they did well.
"We struggled at the start but we improved. It was Todibo's first game with us, and Riqui and Moussa were making their league debuts.
"They all got better as the minutes passed. You have to understand the circumstances which surrounded the match."
Midfielder Arturo Vidal, who did start the game, said Barca's players had been distracted by Tuesday's game against United.
"We were all thinking about Manchester -- those that were here and those that stayed at home," he told reporters. "It is going to be difficult, but we got a good result over there. The Champions League is everyone's dream."