Atletico woes continue with Cadiz defeat
A brace either side of half-time from loanee Juanmi secured an invaluable three points for the 18th-placed Andalusian side and condemned Atletico to a seventh defeat this term.
Atletico's season has hit some turbulence and the loss follows on from defeat over two legs in the Copa del Rey semi-final against Athletic Bilbao and a 1-0 first-leg loss at Inter Milan in the Champions League last 16.
Spanish international striker Juanmi was left unmarked in the box to head in midway through the first half before he sealed the victory with a scuffed finish just after the hour mark.
The first period was defined by a litany of fouls as neither side was able to get into their groove.
Ruben Sobrino got to the byline on 24 minutes and his left-footed cross found the head of Juanmi, who gleefully headed home from five yards out to give Cadiz the lead.
Simeone rang the changes at half-time, replacing Memphis Depay as well as experienced midfielders Saul Niguez and Rodrigo de Paul but to no avail.
It was Juanmi, on loan from Real Betis, who was again the difference maker.
With 64 minutes gone, he latched onto Javi Hernandez's long pass and outfoxed Jan Oblak with an untidy but effective volleyed finish.
The result pushes Cadiz closer to safety as they provisionally move to within two points of 17th place, while it leaves Atletico four behind Girona in third.
Earlier, Valencia climbed to eighth with a 1-0 win at home to Getafe, courtesy of a clever lofted finish by Hugo Duro five minutes before the break.
Later on Saturday, Real Sociedad host struggling Granada and Girona can move further clear of Atletico when they play Osasuna.