ALBION gave the European Champions a fright with a late rally but Demba’s Ba’s 28th-minute strike ultimately proved decisive at a ground where the Baggies have yet to earn a Barclays Premier League point in seven visits.
Chelsea dominated the first half and would have been further ahead at the break had it not been for another fine performance from Ben Foster.
The second 45 proved a scrappy affair but the Baggies grew in confidence during the closing stages and almost nicked an unlikely point, with Petr Cech twice having to be at his best to keep out a free-kick from sub Peter Odemwingie and an unwitting Cesar Azpilicueta header.
Fourth entertained seventh at Stamford Bridge as Steve Clarke made two enforced changes for his first return to his former club as a head coach.
Marc-Antoine Fortune and Graham Dorrans came in for on-loan Romelu Lukaku, who was ineligible to face his parent club, and injured skipper Chris Brunt.
There was a big moment for 16-year-old Academy midfielder Isaiah Brown, who was named on the bench for the first time.
Clarke was welcomed back to his former stomping ground by the on-pitch announcer as he emerged from the tunnel moments before kick-off and was given the warmest of welcomes by both sets of fans.
Albion made a bright enough start in West London but were grateful to a fine piece of goalkeeping by in-form Foster after just four minutes.
Oscar looked certain to score as he made contact with Ba’s perfectly-placed centre but was brilliantly denied by Foster at point=blank range.
In the same minute, Oscar teed up Juan Mata and the Spanish international fizzed a fine volley just past the far post from an acute angle.
However, Albion soon had a shooting chance of their own when James Morrison was felled by Ramires 30 yards out. Steven Reid stepped up to the set-piece and unleashed a ferocious shot which Cech did well to push over.
The Baggies more than held their own for the next ten minutes as the teams enjoyed an equal share of possession.
But the visitors had another let off on 17. A flowing move resulted in Mata whipping in a cross from the right and the unmarked Oscar planted a free header straight at Foster.
Moments later, Ba drilled a fierce shot straight at Foster from the edge of the box.
Chelsea were now keeping Albion pegged back but Oscar was well off target from distance on 22.
There was also a nervy moment when Gareth McAuley attempted to shepherd a loose ball back to Foster, with Eden Hazard breathing down the centre-half’s neck. Thankfully, the Albion No.1 was alert to the danger and hacked the ball out for a throw-in the nick of time.
The Blues pressure was mounting and Foster had to scamper across his goalline to push away a David Luiz free-kick which took a wicked deflection off Youssouf Mulumbu in the Albion wall.
However, Chelsea broke through Albion’s resistance from the resulting, 28th-minute flag-kick. A short corner was fed to Oscar whose deep centre was headed back across goal by Luiz for Ba to tap home.
The hosts had deserved their lead and almost doubled it on the half-hour mark when Mata flashed a fine 18-yard volley a yard wide of the left-hand post.
Albion were struggling to get any forward momentum going and Liam Ridgewell did well in the 38th minute to deflect wide Oscar’s 18-yard half-volley direct from Mata’s corner.
The Baggies’ defence showed they were willing to put their bodies on the line again two minutes later when Jonas Olsson and Ridgewell, again, threw themselves in the way of shots from Oscar and Azpilicueta to protect Foster’s goal.
Albion didn’t threaten again until three minutes before the break when Morrison volleyed wildly over from 25 yards.
That proved the final action of a half in which Chelsea’s expensively assembled side had underlined their class.
It took both teams a while to get going after the break, but Foster was again the first keeper who was called into action when, on 55, he denied Ba at point-blank range inside his six-yard box.
But normal service soon resumed as Albion struggled to get out of their own half.
Chelsea were rightly denied a penalty by referee Kevin Friend when Hazard went to ground after going shoulder to shoulder with Olsson in the box before Clarke rang his first change, replacing Fortune with Odemwingie.
The second half had largely been incident-free and it wasn’t until the 70th minute that Albion won their first corner. However, with the score only 1-0, they were surprisingly still in it.
Albion won another flag-kick on 72 but Olsson could not keep his near-post flick from Morrison’s centre on target.
The Baggies were now growing in confidence and, 13 minutes from time, McAuley saw a deflected header from Morrison’s free-kick loop just wide.
With his former boss and current England chief, Roy Hodgson, watching, Foster excelled again when he pulled off arguably his best save of the game to keep out Oscar’s 15-yard volley from Ba’s tee up. Moments later, he palmed away another strike inside the box from the same player.
But Albion hit back and began to put the Chelsea goal under concerted pressure.
Cech had to be at his best seven minutes from time to push over a stunning 30-yard free-kick from Odemwingie, who had caused real problems since coming off the bench.
From Morrison’s resulting corner, Cech had to produce an equally fine reflex save after Azpilicueta inadvertently headed the ball towards his own net.
Albion just would not lie down and went close on two further occasions in stoppage time.
Morrison found Odemwingie just inside the box and Cech had to make a smart save at his near post to keep out the Nigerian’s left-footed grass-cutter.
Then, in the fifth minute of stoppage time, there was real panic in the Chelsea box. Reid played Morrison’s corner back into the danger-zone and Foster, who had come up for the flag-kick, came within inches of connecting with an ambitious scissor kick. The ball eventually fell to Olsson who miscued wide from 15 yards.
With that chance went Albion’s hopes of bagging a point and the full-time whistle was greeted with a collective sigh of relief from the home fans.
CHELSEA (4-2-3-1): Cech; Azpilicueta, Ivanovic, Luiz, Cole; Ramires, Lampard (c); Hazard (Moses 80), Mata (Mikel 90+4), Oscar; Ba (Torres 87). Subs not used: Turnbull (gk), Terry, Cahill, Bertrand.
ALBION (4-2-3-1): Foster; Reid, McAuley, Olsson (c), Ridgewell; Yacob (Rosenberg 82), Mulumbu; Fortune (Odemwingie 62), Morrison, Dorrans (Thomas 71); Long. Subs not used: Myhill (gk), Jones, Tamas, Brown.
GOALS: CHELSEA – Ba (28).
BOOKINGS: CHELSEA – Hazard (foul 56). ALBION – McAuley (foul 65), Odemwingie (foul 85).
REFEREE: K Friend (Leicestershire).
ALBION STARMAN: Ben Foster.