Impressive Sevilla hands Atletico Madrid its first La Liga loss
"It was an important game to consolidate ourselves against a team that looked unbeatable," Sampaoli said. "We did well against one of the best teams in the world. This victory makes me proud."
"It's going to be tight like this the entire season," Real Madrid coach Zinedine Zidane said.
Atletico, which had the lead coming into the weekend, dropped to fifth place, three points behind Madrid.
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Sampaoli made key adjustments at halftime, allowing his team to take control of the game and earn the hard-fought victory under pouring rain in Seville.
Real Madrid 2, Athletic 1
Real Madrid needed an 83rd-minute winner by substitute Alvaro Morata to earn a hard-fought win against Athletic Bilbao.
Karim Benzema put Madrid ahead just seven minutes into the game at the Santiago Bernabeu, but Sabin Merino equalized in the 27th and held on for most of the match.
Morata, celebrating his 24th birthday, scored from close range less than 10 minutes after replacing Benzema. Athletic goalkeeper Gorka Iraizoz made the initial save but Morata persisted and found the open net off the rebound.
"I feel like a 10-year-old," Morata said. "We won and we are in the lead, it couldn't have been better."
It was Madrid's second straight win after three consecutive draws in the league.
Madrid and Villarreal are the only unbeaten clubs in the league after nine rounds.
Athletic is sixth on 15 points, six behind Madrid.
Villarreal 2, Las Palmas 1
French striker Cedric Bakambu scored the winner in second-half injury time for Villarreal, but it was Las Palmas' Kevin-Prince Boateng who attracted all the attention with a remarkable goal before halftime.
Boateng's side volley from inside the area came after a mid-air, back-heel pass by Pedro Tana, who flicked the ball across the area for Boateng to shoot firmly into the corner.
Still unbeaten in the league this season, Villarreal has won three of its last four games and is in fourth place with 19 points.
Celta 4, Deportivo 1
After a 4–3 loss to Barcelona and a 5–0 defeat against Villarreal, Celta cruised to victory against struggling Deportivo to move to eighth place with 13 points.
Deportivo, which has lost four of its last five games, dropped to 17th in the 20-team standings.