New Year, same old Chelsea. Just as the Blues looked to have finally turned the corner under Claudio Ranieri, Southampton exposed all of their inherent failings at Stamford Bridge.

Try as they might to find greater consistency, Chelsea remain the team with the worryingly soft underbelly who are still prone to capitulating against weaker teams.

First it was Blackburn drawing at Stamford Bridge to a chorus of boos. Then it was Charlton winning 1-0 just after Chelsea had triumphed at Old Trafford.

And now, fresh from wins against Liverpool and Newcastle, Chelsea have collapsed again despite leading 2-1 at half-time as their previously rock-steady defence crumbled away without trace.

Having taken the decision not to restore fit-again Marcel Desailly to the side, Ranieri saw his team concede three goals for the first time this season after changing a winning team at half-time.

Marian Pahars and Chris Marsden added to James Beattie's early opener and then Beattie struck again to confirm a result which undermines any claims Chelsea may have had towards a title challenge.

All credit to a valiant and accomplished Southampton side, however, especially with their character in coming back from a half-time deficit.

While they beat Tottenham on Boxing Day, Gordon Strachan's side had endured a recent mauling by Manchester United and a last-minute defeat by Leeds.

However, there were just seven minutes gone at Stamford Bridge when Beattie put them ahead with a superb 35-yard free-kick.

There looked little real sign of danger when John Terry fouled Pahars but Beattie struck the ball over the wall with tremendous power and accuracy as it curled into the top corner.

Chelsea were soon back in contention as Jimmy Floyd Hasselbaink met Graeme Le Saux's cross with a flicked header that goalkeeper Paul Jones could only parry as far as Eidur Gudjohnsen, who bundled the ball home.

Hasselbaink twice came close to giving Chelsea the advantage as Le Saux was allowed too much space down the left flank, but the game increasingly became a crowded midfield battle.

Then there was astonishment when referee Eddie Wolstenholme took the recent crackdown on diving to a ludicrous new level as he booked Le Saux for falling over at full pace.

Maybe that just woke Chelsea out of their slumber as Gudjohnsen this time turned provider for Hasselbaink as the Dutchman just held his run to beat the offside trap and finish with aplomb.

They have now scored 29 goals between them already this season, but it was in defence that Chelsea suffered as they were taken apart on the break in the second-half.

Ranieri tinkered with his line-up at half-time again, replacing Mario Stanic with Slavisa Jokanovic and moving Frank Lampard to the right side of midfield.

Nine minutes later, they were duly pegged back.

Chelsea appealed for a free-kick when Sam dalla Bona went sprawling but referee Wolstenholme, who was doing little to endear himself to the home crowd, waved play on.

Defender Paul Williams reacted first by immediately spraying a 40-yard pass into the path of Pahars, who beat England hopeful Terry for pace and clipped his finish past Cudicini.

Less than 10 minutes later, Southampton's fearless endeavour was further rewarded as Frank Lampard could only flick on Paul Telfer's corner and Marsden arrived unmarked to head past Cudicini.

If that was not bad enough for Chelsea, there was worse to follow. For Pahars then delivered a searching cross and Beattie was left unattended to volley home from the edge of the six-yard box.

Chelsea inevitably piled on the late pressure, with Hasselbaink, Lampard and Le Saux all threatening, while Gianfranco Zola and Mikael Forssell were now on.

However, there was never any real conviction about the home side as they meekly crumbled to defeat, with Terry's late booking, his fifth of the season, meaning a one-match ban.

It is back to the drawing-board again for Ranieri now.

Teams:

Chelsea: Cudicini, Melchiot, Terry, Gallas, Babayaro (Zola 67), Lampard, Stanic (Jokanovic 45), Dalla Bona (Forssell 84), Le Saux, Hasselbaink, Gudjohnsen.

Subs Not Used: de Goey, Ferrer.

Booked: Le Saux, Terry.

Goals: Gudjohnsen 20, Hasselbaink 45.

Southampton: Jones, Dodd, Lundekvam, Williams, Bridge, Telfer, Delap, Svensson, Marsden, Pahars (Ormerod 82), Beattie.

Subs Not Used: Moss, El Khalej, Petrescu, Fernandes.

Booked: Dodd.

Goals: Beattie 7, Pahars 55, Marsden 64, Beattie 73.

Att: 35,156

Ref: E Wolstenholme (Blackburn).