Carlo Ancelotti said Real Madrid were "still on holiday" in their shock 1-0 loss to Getafe on Sunday while Barcelona overcame their Covid chaos to sneak a tight victory away at Mallorca.
Madrid's surprise defeat was their first in three months and gives fresh hope to the beleaguered chasing pack in Spain, after Eder Militao's early error allowed Enes Unal to score the winner at the Coliseum Alfonso Perez.
"We were on holiday for an extra day," said Ancelotti afterwards. "The team was not the same team that played before Christmas -- less commitment, less concentration.
"We didn't deserve to lose but we ended up with a defeat that could be a wake-up call."
Barcelona were without eight first-team players who had tested positive for Covid last week while a further six were out through injury or suspension.
Xavi Hernandez said on Saturday it was "crazy" the game had to go ahead, with Jordi Alba, Ousmane Dembele and Gavi among those infected while Sergio Busquets was suspended and Pedri, Ansu Fati and Memphis Depay injured.
But a patched-up Barcelona team climbed to fifth, just a point behind Atletico Madrid, after Luuk de Jong's header proved the difference in a 1-0 win over Mallorca.
"With all the absentees, the three points are hugely important for us," Xavi said.
"The first objective this season is to be in the Champions League places and now we are close."
Atletico Madrid claimed fourth spot after beating the high-flying Rayo Vallecano 2-0 to leapfrog Rayo, with Angel Correa scoring both of Atletico's goals.
Atletico and Barca are still 14 and 15 points behind Real Madrid respectively but Sevilla in second will be only five adrift of the leaders, with a game in hand, if they win at Cadiz on Sunday.
Madrid have taken command of the Spanish title race after a superb run of form that included 10 consecutive wins and 15 matches without defeat, their last loss coming at Espanyol on October 3.
But Ancelotti's side were woefully out of sorts in their first outing of 2022 and, aside from a brief spell in the first half, struggled really even to threaten the Getafe goal.
Eden Hazard came on at half-time but again failed to shake his team into life while Karim Benzema was unusually quiet up front. Madrid certainly missed the penetration of Vinicius Junior, who was absent after testing positive for Covid.
"To say we were still on holiday isn't a criticism, it's the same thing that I've said to the players," Ancelotti said.
"We accept responsibility, because the coach was maybe still on holiday as well. We are still top, so we look forward."
Getafe lost eight games in a row earlier in the season but came in on the back of an upturn in form under Quique Sanchez Flores, having gone five games unbeaten, including a pair of wins over Cadiz and Osasuna.
Unal gave them the lead in the ninth minute after the usually dependable Militao was caught napping. The Brazilian went to clear on the edge of his own area but instead took an extra touch, engaging in a tussle with Unal, who robbed the ball and finished past Thibaut Courtois.
Hazard and Marcelo both came on at half-time but neither made much of an impact, with Hazard unable to muster a single attempt on goal. Benzema had a shot blocked, Casemiro saw a half-volley saved and Mariano Diaz headed over, but Getafe deserved their victory.
De Jong has been linked with leaving Barcelona this month but it was his goal that secured a crucial victory over Mallorca, the Dutchman heading in Oscar Mingueza's cross at the back post to make it four games unbeaten now under Xavi.
Barca also needed a stunning, reaction save from Marc-Andre ter Stegen, whose right arm denied Jaume Costa from volleying in an equaliser in injury-time.
Atletico had suffered four consecutive defeats in La Liga for the first time ever under Simeone but Correa's double ensured they bounced back against Rayo, who drop to sixth.