Robert Lewandowski shouldered home a dramatic late winner for Barcelona as they edged Atletico Madrid 2-1 on Saturday to move seven points clear at the top of LaLiga after Real Madrid slipped up.
Second-placed Real were beaten 2-1 at Mallorca earlier on and Barca capitalised at the Metropolitano stadium to take a big step towards defending the league title.
Coach Hansi Flick said the race for the Spanish crown was not over but admitted it was an important victory.
"We have eight games to play and for me nothing is done, we have to stay focused," said Flick.
"The (players) were happy, everyone knows that these were big points today... but everyone knows it's not done."
Marcus Rashford pulled Barca level after Giuliano Simeone opened the scoring for the hosts in the first half.
Atletico midfielder Nico Gonzalez was sent off just before the break and his team dug deep with 10 men to try and avoid defeat, which they almost managed.
Veteran Polish striker Lewandowski had other ideas and used his shoulder to deflect home a rebound from point-blank range after 87 minutes.
"We all knew what happened in the afternoon," Barca defender Eric Garcia told DAZN.
"We knew that if we won today we would be taking a big step (towards the title), so we're very happy."
This was the first of a trilogy of matches between the sides, clashing in the Champions League quarterfinals over the next fortnight.
With little left to play for in LaLiga, Atletico coach Diego Simeone rotated heavily with Wednesday's visit to Camp Nou in mind.
Barca's 18-year-old star Lamine Yamal hit the post with a dinked effort as the game flowed from end to end.
Atletico took the lead in the 39th minute through Giuliano Simeone, the coach's son bursting in behind Barca's high defensive line and slamming past Joan Garcia.
The visitors pulled level just three minutes later, Rashford exchanging passes with Olmo and drilling past Juan Musso on only his third league start since January.
Atletico were reduced to 10 men just before halftime when Gonzalez scythed down Yamal on the edge of the box as he ran towards goal.
Barcelona defender Gerard Martin was dismissed early in the second half as he thumped the ball away but then clattered Thiago Almada with a high foot. However after a VAR review the red card was revoked, much to Atletico's fury.
Barca struggled to make their numerical advantage count until late on when Joao Cancelo's shot was pushed out by Musso, only for substitute Lewandowski to cleverly turn home with his shoulder.
"When it was 11 against 11 we were better, that gives us confidence," said Atletico stopper Musso.
Flick said both teams would be better in the Champions League quarterfinal first leg on Wednesday.
"There is the Champions League, where every player has 5-10 per cent more to give," said Flick.
MURIQI REDEMPTION
Vedat Muriqi's late strike secured Mallorca a shock late win over Real Madrid.
Alvaro Arbeloa's side thought they had rescued a point after Eder Militao nodded home with two minutes remaining to level Manu Morlanes's opener before Muriqi pounced to help the hosts climb to 17th.
"For me it is easy to see but the hard thing is for the players to know that without giving 200 per cent today, we were not going to win," Arbeloa told reporters.
"We were on top in the first half but because of one mistake, they scored. Here if you slip up for a moment... you end up paying the price."
Arbeloa started the game with Vinicius Junior on the bench, with Tuesday's Champions League quarterfinal against Bayern Munich in mind.
Mallorca goalkeeper Leo Roman saved well from Madrid's top goalscorer Kylian Mbappe and Arda Guler, before Mallorca nosed ahead.
Morlanes lost Eduardo Camavinga and tucked Pablo Maffeo's cross past Andriy Lunin.
Arbeloa sent on Vinicius, Jude Bellingham and Militao for his first appearance since December after injury.
Madrid huffed and puffed but to little avail until Militao nodded home from a corner late on.
However there was a sting in the tail for Madrid. Muriqi, second top scorer in the division behind Mbappe with 19 goals, lashed home in stoppage time.
The striker was visibly emotional after scoring, having missed a penalty in the team's previous game, a defeat by relegation-battling rivals Elche.
"It's been two difficult weeks... emotions and nerves get the better of me, I'm human," said Muriqi, who also missed out on World Cup qualification with Kosovo in a play-off against Turkey.