Marco Asensio struck a last-gasp winner as Real Madrid edged to a 1-0 win at Leganes in the first leg of their Copa del Rey quarter-final on Thursday.
Zinedine Zidane's men, 19 points behind Barcelona in LaLiga, had won one of their last five games in all competitions, amid reports the Frenchman could leave the club at the end of the season, and they looked set to be held at Butarque.
But after Leganes had shone on their first appearance at this stage of the competition, Asensio came up with a cute near-post finish from Theo Hernandez's cross to put Madrid in firm control of the tie.
Madrid were held at home by lower-tier clubs Numancia and Fuenlabrada in previous rounds after first-leg away wins and they struggled to respond to Saturday's 1-0 defeat at the hands of Villarreal, with Mateo Kovacic missing a golden first-half chance.
Jose Naranjo and Claudio Beauvue forced smart stops from Kiko Casilla and Marcos Llorente headed against his own crossbar, adding to the sense of injustice at Leganes' defeat.
Madrid were poor for large parts of the contest, but Asensio's dramatic impact may serve to ease the growing pressure on Zidane ahead of Wednesday's return leg at the Santiago Bernabeu.
GOLAZOOOOOOOOOO! What a goal!!! @TheoHernandez produced an excellent cross from the left and @marcoasensio10 expertly volleyed home, at the near-post, from iust outside the six-yard box!@CDLeganes 0-1 #RealMadrid#RMCopa | #HalaMadrid— Real Madrid C.F. (@realmadriden) January 18, 2018
Madrid were forced into an early change, introducing birthday boy Nacho at the back for the injured Jesus Vallejo, but Zidane's men made a flat start to the game and had to wait until the 23rd minute for a sight of goal, which Raphael Varane headed over the crossbar.
Javier Eraso rifled a long-range drive off-target as Leganes, on a four-game winning streak at home, found a foothold in midfield midway through the first half.
But Madrid should have taken the lead when Kovacic picked Ruben Perez's pocket 25 yards from goal, only for the Croatian to slide his shot tamely wide of the near post.
Gerard Gumbau got a vital touch to deflect Dani Carvajal's drive wide before Lucas Vazquez just missed Asensio's cross on the stroke of half-time.
Casilla had to react sharply to block a close-range Naranjo effort after 56 minutes, Diego Rico nutmegging Carvajal with a superb backheel to send the winger clear.
And Leganes came even closer to breaking the deadlock when Llorente could only direct a free-kick against the woodwork, with Casilla stranded.
Zidane brought on Luka Modric and Isco for more midfield control but Leganes substitute Nordin Amrabat had a more immediate impact, hooking a volley wide moments after his introduction.
With the game becoming stretched, Modric played Vazquez through but Nereo Champagne made a fine block, denying the Spain winger his fourth goal in the competition.
Casilla sharply palmed away a Beauvue volley destined to fly inside his left-hand post with 15 minutes to go and when Kovacic again finished meekly, Leganes looked to have held on.
It was not to be.
Clumsy for the most part, Theo had endured a poor game at left-back but his whipped delivery was perfect for Asensio to get in front of his man to flick home a vital goal for Zidane's Madrid.
|Bills release Richie Incognito from reserve/retired list|
|Gentry and Pelicans want Cousins back in New Orleans|
|MLB extends Blue Jays closer Osuna´s administrative leave|
|Lloris, Jedinak and Kjaer ask FIFA to allow Guerrero to play at World Cup|
|Wolfsburg preserve Bundesliga status after play-off win over Kiel|
|Zidane was my idol and always will be - Wijnaldum|
|Liverpool ready to fly out of the blocks in Kiev - Henderson|
|Montreal Impact 0 LA Galaxy 1: Ibrahimovic sent off for slapping opponent|
|Real Madrid v Liverpool: Salah, Ronaldo lead the line in combined XI|
|Bertens keeps hat-trick hopes alive in Nuremberg|
|Monfils and Mannarino fail to fly the flag in Lyon|
|Morata, Fabregas, Herrera and more in Spain´s World Cup rejects XI|
|Reina to face FIGC hearing|
|Emery set to be appointed by Arsenal - reports|
|LeBron ´appreciative´ of hometown effort to put up statue of him|
|Cazorla leaves Arsenal after injury nightmare|
|Derby´s Rowett seeks permission for Stoke talks|
|Messi physically and mentally ready for the World Cup, Sampaoli proclaims|
|Murray expected to return at Rosmalen Grass Court Championships|
|More to Madrid than just Ronaldo - Robertson|
|Wolff: Red Bull and Ferrari favourites in Monaco|
|Iniesta hailed by Xavi as ´the most talented player in the history of Spain´|
|If you Googled ´European nights´, Liverpool would be top result - Klopp|
|Icardi cut from Argentina World Cup squad|
|Test recall a ´fantastic surprise´ for Buttler|
|Klopp needs Premier League to be a Liverpool great – Johnston|
|Salah is ´definitely´ world´s best - Lovren|
|Rhinos captain Watkins ruled out for eight months|
|No clue - Klopp defiant over Can to Juventus claims|
|Younis tips Babar for Pakistan greatness|
|Germany squad numbers hint at World Cup good news for Neuer|
|WATCH: Moto3 rider makes spectacular jump over crashed rival|
|Leaving out Morata ´painful´ for Spain boss Lopetegui|
|Gustard to leave England role for Harlequins|
|Nainggolan retires from Belgium duty after World Cup snub|
|Spain striker Morata misses out on World Cup selection|
|LeBron or Kawhi could lead Lakers to the Finals - World Peace|
|Serena steps up Roland Garros training ahead of French Open|
|Nainggolan left out of Belgium´s World Cup squad|
|The long goodbye: Iniesta sits alone in Camp Nou after final Barcelona match|
|Wane to leave Warriors at end of season|
|Dr Fury will see you now - Tyson plans future career in medicine|
|Harden, D´Antoni rue ´soft´ Rockets performance in Warriors drubbing|
|Liverpool players can change their lives in Kiev, says Gerrard|
|Real Madrid v Liverpool: Can great deeds of the past fuel the bid for Champions League glory?|
|Wash your mouth out! - Curry´s expletive outburst earns scolding from mother|
|Rakitic lost for words as Iniesta heads for Barcelona exit|
|Conte: Chelsea must overhaul squad to change style|
|Johnston: Liverpool can´t lose Suarez, Coutinho and Salah!|
|Messi: I like Griezmann, he´s one of the best|
|Ohtani says he´s not good enough for Home Run Derby yet|
|Mendy: France are eyeing World Cup glory|
|Scott accepts two-week ban for Walker punch|
|Braves rally for six runs in the ninth to defeat Marlins|
|MLS Review: Red Bulls upstage Atlanta thanks to Wright-Phillips brace|
|Warriors breeze past Rockets in game three|
|We have a quality squad – Man City chairman hints at caution in transfer market|
|Wise cruises to maiden PGA Tour victory at Byron Nelson|
|Matic: United can fight for Premier League and Champions League with experience|
|Golden Knights GM on Stanley Cup Finals berth: I don´t know how we did it|
|I did a ´s*** job´ defending LeBron James – Morris|
|Dembele suffers sprained right ankle|
|We know Fellaini´s not going to renew with United – Mirabelli suggests Milan move|
|Cavs´ Lue not satisfied with just one win|
|They even whistled at Torres – Simeone backs Griezmann|
|I arrived as a boy, I leave as a man – Iniesta in emotional Barcelona farewell|
|Lingard: Wembley loss my worst feeling in football|
|Cahill: Conte uncertainty affecting Chelsea|
|Sarri has run out of time – Napoli chief De Laurentiis|
|Barca boss Valverde salutes departing Iniesta|