Chelsea rebels return at wrong time
Luiz, Costa must recover from hapless display as Spurs catch up
David Luiz picked the wrong game to bring back his bad self.
Rather like a club DJ, the Chelsea defender has an alter ego. He's not so much Jekyll and Hyde as he is Jekyll and Hopeless.
The latter returned at Crystal Palace to slip on a banana skin and offer a slither of hope to second-placed Tottenham Hotspur.
Until the 2-1 home defeat on Saturday, Luiz had conveyed an aura of calm reliability that was unsettling because it was unfamiliar.
Before Antonio Conte brought him back to Stamford Bridge, the Brazillian was always car-crash viewing; explosive, sometimes horrific, but strangely captivating.
Until Palace turned up at the Bridge, Chelsea had lost just once at home in 18 games and Luiz was a major contributor to that impressive statistic. He was practically boring in his dependability.
LUIZ A LIABILITY
Without his consistency, Conte's back three could not have worked. And it didn't against Palace, when Luiz's consistency finally eluded him.
Wilfred Zaha's equaliser, which cancelled off Cesc Fabregas' early opener, owed more to a dithering Cesar Azpilicueta, but Palace's winner was all down to Luiz.
His unfortunate ineptitude enabled Christian Benteke to look a potent attacking threat, instead of the hapless bruiser who'd trudged through matches without a league goal since January.
Suddenly, the Belgian was a world-beater. He skipped past Luiz with alarming ease, collected the return from Zaha and chipped a neat finish over Thibaut Courtois.
Luiz had drifted past the game's periphery and towards 2013, when he often entertained and exasperated in equal measure.
This was Luiz at his retro worst, a liability at the back that exposed Conte's back three as a tactical necessity, rather than a choice.
Azpilicueta only added to the jitters as Palace offered hope to Chelsea's upcoming opponents (including Manchester City in midweek).
Quick one-twos coated in a neat sheen of pace can kill off Conte's famed back three.
It's a barely perceptible chink in the armour and even the greatest are allowed a bad day at the office, but Conte's comments were telling.
He's desperate to get the 21 points required as quickly as possible to make the title a mathematical certainty and rule out a dramatic overhaul at White Hart Lane.
Conte's back three tinkering was still derived from luck, rather than judgment.
Tottenham manager Mauricio Pochettino, on the other hand, continues to pull tactical rabbits from an increasingly threadbare hat.
Against a stubborn Burnley, Pochettino moved quickly to deal with his goal-shy players in Harry Kane's protracted absence.
When Victor Wanyama and Harry Winks were injured early, Pochettino immediately shifted a back three to a four, moved Eric Dier in front of defence and pushed on Mousa Dembele.
Christian Benteke has scored in his past three English Premier League appearances at Stamford Bridge, each with a different club (Aston Villa, Liverpool and Crystal Palace).
Spurs scampered away like birds released, ending Burnley's resistance and cutting Chelsea's lead to seven points with nine games remaining.
It's highly doubtful they'll claw back the deficit, but it's not Tom Cruise hanging off the side of a plane. The mission is merely improbable, not impossible.
Right now, Pochettino will take that, particularly when the No. 9 at Chelsea was present, but not particularly dangerous.
Late in the contest, Conte was a picture of pained frustration, hopping on the touchline as if shaking out his anger.
Diego Costa had missed again. On this occasion, he had steered an open header wide from six yards, but the charge sheet was long.
He was unlucky to find a Palace goalkeeper in inspired form, but his negligence was also self-inflicted. Several low crosses were teased across the six-yard box, but Costa wasn't on the end of any of them.
His recent precision had deserted him, replaced with that customary pout.
Sometimes, rage propels the volatile Spaniard. Against Palace, it restricted him.
Conte will believe it's an untimely blot on an otherwise pristine landscape, but Man City know there are at least two options available to them.
Isolate Luiz and irritate Costa. It's a long shot, but until Palace pick-pocketed Stamford Bridge, there was no shot.
Right now, Chelsea's rivals should clutch every straw they can. The title race remains on life support, but there's at least a faint pulse now.