Madrid was held to a goalless draw by Real Betis on a potentially pivotal day in the title race, a few hours after 10-man Barcelona had battled to a 1-0 home win against Valencia.

Madrid still has to travel to Barca in a fortnight, but Opta's league predictor now gives the reigning champion just a 9.8 per cent chance of finishing top of the table.

After seeing his side held for a second league game running, having drawn 1-1 against Atletico Madrid last week, Ancelotti accepted Madrid have their work cut out.

"It's not impossible," he told Movistar when asked if there is any hope of catching Barca. "It will be very difficult, very complicated, but we have no doubt we'll fight until the end.

"Of course these results are affecting the team. If it doesn't then you have no room to improve." 

Madrid is without a win in three games after going down 1-0 to Barcelona in the first leg of its Copa del Rey semi-final on Friday (AEDT).

The European champion has failed to score in its past two games, which is as many as in their previous 39 matches.

After being unable to register a shot on target against Barca and in the first half against Betis, Madrid did at least improve in the second half as Claudio Bravo made five saves.

"It was a difficult match for us," Ancelotti said. "We know we could have done better in terms of efficiency in attack. We had opportunities but lacked efficiency.

"This is the reality. We've scored only one goal in our past three games, and it's clear to see what we're missing from set-pieces. We have the quality to be doing better.

"We know we have to improve in that regard. We know in moments like this we have to do better."

Karim Benzema thought he had given Madrid the lead in the 15th minute, only for his free-kick to be ruled out after a VAR check showed the ball hit Antonio Rudiger on the arm.

Madrid has now played out six goalless draws with Betis in the league this century – against no side has it done so more often – with this latest stalemate particularly costly.

Dani Ceballos, who wasted one of a few good chances that fell the visitor's way in the second half, echoed Ancelotti's sentiment that his side must keep on fighting.

"There are still games left and we are not that far away [from Barcelona]," he said. "The DNA of this club is to fight until the end. Where there is an opportunity, Madrid will fight.

"We have a very important game against Espanyol next Saturday in front of our fans. We also have Barcelona to play, so we have to do our best before the international break."

Betis fell short of registering a fourth straight league win for the first time since December 2021, but head coach Manuel Pellegrini was happy to come away with a point against his former club.

"Winning games is important, but if you can't do that then it's better to not lose," said Pellegrini, whose side are three points adrift of fourth-placed Real Sociedad.

"I think it was a fair point for both teams. There are many teams in the fight for the top four and others will also start to challenge."