Real Madrid beat bitter rivals Barcelona 2-0 in Sunday's clasico, with captain Sergio Ramos saying their fate is in their own hands to go on and win a first La Liga since 2017.
Following a week in which they beaten at home by Levante and in Europe by Manchester City, Madrid answered their critics in the most emphatic way with victory at the Bernanbeu courtesy of a deflected effort from Brazilian teenager Vinicius Jr and a goal from substitute Mariano to move a point ahead of Barca at the Liga summit.
Crucially, Zinedine Zidane's side also have the better head-to-head record in the event both sides finish level on points.
Real captain Ramos underlined the importance of the victory for his side after a week in which they were reeling from a Champions League last 16, first-leg defeat at home to Manchester City and a shock 1-0 Liga loss away to Levante.
"This was a unique opportunity to put our own fate in our own hands for the rest of the season, against a brilliant side but with our fans on our side," he said.
"We were relentless in the second half and once we got the goal we made sure we didn't sit back and instead we set out to kill the game off and that's what we did.
"When results don't go your way you feel in debt to the fans and we needed a day like this. We wanted to win and now we want to make it count by winning the title."
Barcelona had bossed the first period and twice could have taken the lead but were powerless to stop Real after the interval and their impotence was summed up when Lionel Messi raced towards goal but was easily tracked down by Marcelo.
Marcelo's tackle got as loud a cheer as the goals from Madrid's fans who had not been able to toast a league win over Barca at the Santiago Bernabeu since 2014.
The long-awaited victory was confirmed by an unlikely source in forward Mariano, who had only just come off the bench to make his first league appearance of the season.
"We deserve our victory for everything we did, in attack and defence," Zidane told reporters. "It has been a complicated week for us and we had the chance to turn things around and we did that.
"But this win also doesn't change anything. We have a long way to go and we have to continue. We've got three important points but we'll have more difficult games and we will be criticised again."
Lionel Messi, Arthur Melo and Antoine Griezmann each missed clear opportunities but Real came out far stronger after the break.
"We controlled the game in the first half, which was the worst I have seen Madrid play in all the years I have played at the Bernabeu," Barca defender Gerard Pique told reporters.
"We had a chance to make a real statement and if we had taken our chances they would have had a mountain to climb.
"They come out of this game feeling very strong while we feel down but we are not out. I think there is still time for us to win the league."
Barca midfielder Sergio Busquets believed his side deserved better.
"We played very well in the first half then in an unfortunate move they score thanks to a deflection. We had a great chance to open up a big gap but it wasn't to be," he said.
"There's a long way to go in the season and we have to remember the positive things and how well we played in the first half."