Substitute Alvaro Negredo scored the winner in the 63rd minute and Cadiz were able to withstand some late pressure from Barca to hold on to the three points.
The home side, who beat Real Madrid earlier this season, took an early lead through Alvaro Gimenez but Barca struck back in the second half when Pedro Alcala turned Jordi Alba's cross into his own net. Barca's joy was short-lived, though, with Negredo scoring just five minutes later and Ronald Koeman's team were unable to come back for a second time.
in the first half, pushing Cadiz back and eventually getting the equaliser -- albeit with a slice of luck -- they deserved at the time.
The euphoria of three wins in a row over the past 10 days was clouded by doubts over the opposition Barca had faced. On Saturday, the idea that they have turned a corner was quashed by Cadiz. Worst of all for Barca was that they shot themselves in the foot with defensive mistakes, gifting their opponent two goals. Oscar Mingueza was at fault for the first goal and Clement Lenglet cost them the second.
Barca are already 12 points behind leaders Atletico Madrid and it's going to take a huge change in performances to win the title from here.
Manager rating out of 10
5 -- Koeman went with Lionel Messi, Antoine Griezmann and Philippe Coutinho in attack but the problem when they all play is that there's no width. Once again, the Dutch coach was unable to affect a game with his changes. That's six times his Barca side have fallen behind and they've not come back to win any of those matches, losing four and drawing two.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Marc-Andre ter Stegen, 6 -- Was completely exposed at times given Barca were all-out attack from the eighth minute on but managed to make a couple of big saves when faced with one-on-ones.
DF Sergino Dest, 6 -- An outlet in attack and always prepared to take his man on. However, he missed one of Barca's best chances to equalise, shooting wide after Busquets teed him up.
DF Oscar Mingueza, 5 -- His poor attempt to head a corner clear led to the opening goal, although he argued he had been fouled, which knocked his balance.
DF Clement Lenglet, 4 -- Let the ball bounce in front of him from Alba's throw-in, allowing Negredo to nip in and score Cadiz's second. Also booked. A tough night for the French defender.
DF Jordi Alba, 5 -- Made Barca's goal but then contributed to Cadiz's second by rushing a throw-in and putting Lenglet in trouble.
MF Sergio Busquets, 6 -- One of his better performances of the season, which isn't saying too much. A clever pass to set up Dest in the second half was a particular highlight.
MF Frenkie de Jong, 6 -- Was everywhere, starting in midfield and finishing in defence, but without really having the impact on the game Barca need from him.
FW Lionel Messi, 6 -- Started well, re-energised by recent rests, but grew frustrated as the game went on. Came close to scoring from a corner and drew a couple of saves from the goalkeeper, but his luck was out.
FW Antoine Griezmann, 5 -- Didn't stop trying but wasted the ball too much following back-to-back good performances in Barca's previous games.
FW Philippe Coutinho, 4 -- Missed a good early chance and killed too many Barca attacks before being taken off at half-time.
FW Martin Braithwaite, 5 -- His three-game scoring run ended against a compact Cadiz side. Hardly allowed a sniff.
MF Pedri, 6 -- Worked hard and pressed intelligently but unable to turn the match in Barca's favour.
FW Ousmane Dembele, 6 -- Came on at half-time but his qualities suit a more open game.
FW Francisco Trincao, N/R -- Got into a couple of good positions and had some nice touches but his delivery let him down.
MF Miralem Pjanic, N/R -- His contribution in the 10 minutes that he was on the pitch makes you wonder why he wasn't brought on earlier.