CRAZY defending has left both Chelsea's Champions League campaign and their manager's job hanging by a thread.

It got worse for Andre Villas-Boas when he discovered John Terry’s knee injury requires exploratory surgery and an absence of six to eight weeks.

Napoli could have had a dream start in the 10th minute, when Edinson Cavani was put though in acres of space for a one-on-one with Petr Cech (pic). But the keeper pulled off a fine save to palm the ball onto the post.

Napoli surged forward making pretty little triangles as they did it. Chelsea occasionally went Route One with a big goal kick.

Christian Maggio came in from the left and struck a fierce shot at Cech, which he again managed to push away.

By now Napoli were dominant – but Juan Mata hadn't read the script.

Daniel Sturridge delivered a low cross from the right, missed by the retreating Paolo Cannavaro, Mata ran in and side footed home. Half an hour gone, and little impact for Chelsea yet somehow 0-1 ahead.

But the lead was short-lived. Ezequiel Lavezzi found himself on the edge of the Chelsea box with his first goal-scoring chance, and the resulting shot was laced with venom and firepower – a deserved equaliser for the Italians.

And that disappointment was turned to abject misery when the hosts took the lead on the stroke of half time as Cavani beat Branislav Ivanovic to knock the ball in with his shoulder.

Chelsea opened the second half looking the much stronger side – and they had more than one chance to level the game again.

But, as so often this season, they were never far away from kamikaze defending.

David Luiz chickened out of a tackle as Hugo Campagnaro charged down the Chelsea right. The ball was squared and Cech ran at it only to completely miss. It was routine bread and butter stuff for Lavezzi to hammer into an almost empty net for his second, and Napoli's third.

The Italians could have had a fourth when Cole saved off the line late on.

Back at Stamford Bridge, 2-0 will be enough. But for a team that seemingly can neither score nor defend with any reliability – the chances are slimmer than Victoria Beckham's new outfits.