Atletico Madrid missed the chance to move back into second place in LaLiga as they were held to a 0-0 draw at Leganes for a second successive season.
Having dropped down a place in the table following Sevilla's 2-0 win over Malaga earlier on Saturday, Diego Simeone's side turned in a lethargic display against their spirited city rivals at the Estadio Municipal de Butarque.
Defenders Jose Gimenez and Diego Godin came the closest to scoring for the visitors, while Leganes twice forced Jan Oblak into action after the interval.
The disappointing result ends a tough week for Atletico; they surrendered a lead to lose 2-1 to Chelsea in Champions League action on Tuesday, suffering their first defeat at the Wanda Metropolitano.
Simeone made four changes to the side that started the midweek loss, opting to field three centre-backs as Saul was pushed wide to the left to cover for the injured Filipe Luis.
The visitors came close to scoring inside 90 seconds as their first corner saw Gimenez nearly force a loose ball home from close range, his toe-poked effort going the wrong side of the left post.
However, after that close call in the opening stages, Atletico struggled to find a way through a stubborn Leganes defence that had conceded just three goals in their previous six league outings.
Saul, operating in an unaccustomed role on the flank, smashed a left-footed drive to force a smart save from Ivan Cuellar, while Angel Correa was unable to react quickly enough to Antoine Griezmann's cut-back cross from the right.
Leganes' best chance of the first half fell to Claudio Beauvue, who poked wide with his right foot when meeting Alexander Szymanowski's low cross from the left with a first-time volley.
3 - Claudio Beauvue had as many shots (3) as passes attempted (3) in the first half against Atletico. Islet. pic.twitter.com/7uMfdzFIAH-- OptaJose (@OptaJose) September 30, 2017
The home team - who finished 17th last season to retain their top-flight status - threatened more in attack after the break.
Oblak was fortunate Gabriel's well-struck drive was aimed straight at him, although the goalkeeper did need to produce a dive to turn away a rising shot from Leganes's half-time substitute Nabil El Zhar.
Having decided against making changes to either formation or personnel at the break, Simeone sent on Yannick Carrasco, Fernando Torres and Sime Vrsaljko - who replaced Griezmann - in the hope of sparking Atletico into life in attack.
Yet despite the additional firepower, their best chance fell to a player normally better known for his abilities in the opposite box, as Godin's looped header from a left-wing cross forced Cuellar into a diving stop low to his left.
While the stalemate maintains Atletico's unbeaten away record in all competitions this season, it was hardly the result - or performance - Simeone and his players hoped for after the demoralising defeat to Chelsea.