HT Chelsea 0-1 Birmingham: New low looms for Villas-Boas

Chelsea's season threatened to hit a new low as more inept defending handed Birmingham a shock half-time lead in today's FA Cup clash at Stamford Bridge.

Sunday's training-ground summit failed to have the desired effect on the home side as Andre Villas-Boas' players once again badly let down their under-pressure manager.

More calamitous defending allowed David Murphy to fire an under-strength Birmingham ahead, although the visitors needed a world-class Colin Doyle save from Juan Mata's penalty to maintain their lead.

Frank Lampard, Michael Essien and Jose Bosingwa all missed out as Chelsea made four changes.

Ramires, John Obi Mikel and Gary Cahill were recalled after injury and illness, Ryan Bertrand was handed a rare start at left-back for the injured Ashley Cole, while Didier Drogba and Salomon Kalou were surprise substitutes following the African Nations Cup.

Npower Championship promotion chasers Birmingham made five changes, drafting in Colin Doyle, Pablo Ibanez, Morgaro Gomis, Nathan Redmond and Adam Rooney.

Defeat was unthinkable for a Chelsea side who had not won since their fourth-round victory at QPR, slumping to fifth in the Barclays Premier League.

That had piled the pressure on Villas-Boas, who admitted his "project" no longer enjoyed the support of all of his players.

But the Portuguese insisted he retained the full backing of billionaire owner Roman Abramovich, while his position was strengthened yesterday when Guus Hiddink became manager of Anzhi Makhachkala.

That did not stop the travelling fans singing, "You're getting sacked in the morning", as Chelsea toiled.

They were almost embarrassed when David Luiz's attempted clearance deflected off a Birmingham head before Stephen Carr was forced off injured, replaced by Jonathan Spector.

Villas-Boas had branded last weekend's defeat at Everton the "worst performance of the season" but this was no better and the calamitous defending that cost them at Goodison returned when they fell behind in the 20th minute.

Luiz and Raul Meireles failed to deal with a near-post corner and the ball bounced twice in the six-yard box before it reached Murphy, who drilled home at the far post.

Chelsea finally woke up and urgent attacking immediately won them a penalty when Wade Elliott tripped Ramires - but Doyle produced an excellent save to tip Mata's spot-kick onto the post.

Curtis Davies produced a brilliant interception to stop Fernando Torres reaching a cross from Daniel Sturridge, who then screamed in vain for another penalty when he crumpled under Ibanez's challenge.

Luiz tried to inject some inspiration when a typical surge forward saw Jordon Mutch rightly booked for the crudest of challenges, which the defender almost punished with a superb free-kick that Doyle tipped over.

Sturridge then unleashed a blistering volley that just dipped too late and Mata directed a header too close to Doyle before Chelsea trudged off to muted jeers.