Atletico Madrid ended a miserable week with a dramatic defeat as Cadiz claimed a controversial late 3-2 LaLiga win.
Knocked out of the Champions League group stages in astonishing fashion with a 2-2 home draw to Bayer Leverkusen in midweek, Atletico fell behind after 27 seconds to Theo Bongonda's fastest LaLiga goal of the season.
Alex Fernandez looked to have sealed it for the hosts nine minutes from time only for a Luis Hernandez own goal and a stunning Joao Felix drive to pull Atletico level.
Yet there was a remarkable twist in the tale in the eighth and final minute of injury time when Ruben Sobrino turned home Ivan Alejo's cross, the goal allowed to stand by VAR despite him appearing to do so with his arm.
Cadiz were ahead inside half a minute as Alfonso Espino pursued a ball down the left and produced a low cross for Bongonda to slam into the bottom-left corner.
A fine reflex save from Jeremias Ledesma added to Atletico's frustration in the second half as he denied Angel Correa following an excellent Yannick Carrasco delivery.
Cadiz had a member of the backroom team sent off for throwing the ball at substitute Joao Felix on the hour mark, but their three points looked safe after Fernandez's superb half-volley flew in off the bar.
Joao Felix, perhaps inspired by that earlier incident, almost single-handedly levelled matters. His overhead-kick was diverted home by the unfortunate Hernandez and Ledesma had no answer to his vicious 89th-minute long-range strike.
The Portugal international sent an unmarked header wide in added time and his failure proved costly when Cadiz broke at the death and Sobrino converted in hugely contentious fashion.
What does it mean? - Atletico slip up in Champions League fight
Having seen their Champions League ambitions ended much earlier than usual, Atletico slipped up in their bid to secure a top-four finish this season.
They remain just a point ahead of fourth-placed Real Sociedad and three clear of Real Betis in fifth. Atletico are fortunate those sides play each other on Sunday. Cadiz remain in the bottom three after only their second win of the season.
Atletico start and finish badly
Having conceded the quickest goal of the season, a frantic finale saw Diego Simeone’s men surrender the latest LaLiga goal against them this century, Sobrino finding the net eight seconds into the 99th minute.
Rare away day blues
Atletico had won five and drawn one of their previous six away games in LaLiga this season and would not have expected their first loss to come at Cadiz, who beat the Los Colchoneros for the first time in eight home league matches.
Attention turns to securing a Europa League spot when Atletico face Porto in their final Champions League game of the season on Tuesday. They then host Espanyol a week on Sunday. Cadiz visit Getafe a day earlier.