Neymar was sent off as Barcelona's title hopes suffered a shock setback with a 2-0 defeat against Malaga in Saturday's LaLiga encounter at La Rosaleda.
Luis Enrique's men would have moved level on points with Real Madrid with a win following the capital side's earlier draw against Atletico Madrid, but the Catalans endured a miserable evening as they returned home empty-handed instead.
Sandro Ramirez dealt his former club's hopes of going top of the league a blow before the break when he made the most of some poor defending from Jeremy Mathieu.
And things went from bad to worse after the interval with a second booking for Neymar - his first red card in LaLiga - following a reckless foul on Diego Llorente near the corner flag.
Jony then added a second in stoppage time at the end of counter-attack as the champions chased a way back into the game that never materialised.
Barcelona had every reason to be confident heading into the encounter, having gone unbeaten at the Rosaleda in the league since 2003, but the scoreless draw from the reverse fixture was an indication that Malaga would not be pushovers.
10 - Barcelona have not lost in their last 10 trips to La Rosaleda in La Liga (W8 D2), last losing there back in 2003 (5-1). Memory. pic.twitter.com/1RWdYDhj6t-- OptaJose (@OptaJose) April 8, 2017
Michel's men drew extra confidence from their 1-0 win over Sporting Gijon in midweek, thus ending a six-game winless streak, and they frustrated Barcelona for a second time in 2016-17 following a strong display, Sandro and Jony the heroes for the hosts.
The result means Barcelona remain three points off the pace, while leaders Madrid still have a game in hand.
Barcelona were in charge right from the off and Luis Suarez came close to handing the Catalans the lead in the 16th minute. The Uruguay international did well to bring down Jordi Alba's long ball after beating the offside trap, only to then aim a shot straight at goalkeeper Carlos Kameni from inside the area.
Malaga slowly grew into the game from there on and Recio could have handed his side a surprise lead halfway through the first half after a poor pass from Marc-Andre ter Stegen, but the midfielder aimed wide from 30 yards out as the Barcelona goalkeeper was fortunate not to be punished for his sloppy play.
And the hosts did go a goal up when Sandro found the net following a rapid counterattack in the 32nd minute, beating Ter Stegen with a low shot at the near post after some unconvincing defending from Mathieu.
Barcelona continued to dominate possession after the break, but they nearly went two goals down in the 57th minute after Sandro did well to set up Juanpi in a dangerous position, the Venezuelan midfielder aiming a shot straight at Ter Stegen.
A superb individual moment from Neymar then almost resulted in the equaliser on the hour mark, but the winger saw his shot from a narrow angle hit the upright before bouncing wide for a goalkick.
The Brazilian's frustrations got the better of him in the 65th minute and referee Jesus Gil Manzano saw no other option but to show the attacker his second yellow card of the evening after a reckless challenge on Llorente.
Malaga thought they had doubled their lead when Adalberto Penaranda had the ball in the net after a quick break, but the goal was questionably chalked off for offside.
The linesman's decision would have no influence on the final result, however, as Malaga got their second goal after all in the dying minutes. Pablo Fornals coolly laid the ball off for Jony after yet another counter-attack and the substitute had no trouble firing home to seal the win.