Rafael Benitez was left to rue Real Madrid's error-riddled second-half performance and their inability to close out the match after surrendering the lead to lose at Sevilla in La Liga on Sunday.
Madrid's unbeaten record under Benitez was ended by Unai Emery's men, who scored two goals in the second half to win 3-2.
Sergio Ramos' 22nd-minute opener seemingly had Madrid on course for an eighth victory of the league season.
But the captain injured his shoulder in the process of scoring and the visitors subsequently crumbled at Estadio Ramon Sanchez Pizjuan.
Ciro Immobile levelled proceedings nine minutes before the break, and Ever Banega and Fernando Llorente completed Sevilla's comeback in the second half.
Fit-again attacking midfielder James Rodriguez came off the bench and netted a 93rd-minute consolation for the visitors, with Benitez lamenting Madrid's failure to react after a promising start to the match.
"We played 30 very good minutes, lots of control, in all levels. Then we let them score at dead ball. That changed the game," Benitez told reporters after Madrid lost top spot to reigning champions Barcelona.
"From [the] second goal we started to make mistakes, they took advantage and scored a third. We came back and scored late, but it wasn't enough.
"That was lesson from [the] game … [in the] second half we were not able to manage the situation.
"We lacked know-how ... we had game under control, should've killed it, our mistakes brought them back. We couldn't react.
"At 3-1 it's difficult to react, players didn't know how to control the situation when the result was [going] against us."
Madrid's first match back after the international break is the eagerly anticipated Clasico at home to Barca on November 21.
