A single Demba Ba goal, scored from close-range in the first half, gave Chelsea a third home league win in a row.
The Blues had the chances for more goals, Oscar in particular having a frustrating afternoon in front of the target, but it was a game that only found a high gear on a few occasions. The handful of times West Brom did threaten the Chelsea goal they found Petr Cech on-form and unbeatable. There was some neat approach play at times from the home team who claimed a deserved victory.
Frank Lampard returned to midfield to become Chelsea's joint third highest appearance maker of all-time and played alongside Ramires. Ahead was Juan Mata making it 100 Chelsea games in less than two years for the Spanaird who operated behind the returning Ba, with Oscar and Eden Hazard the wide midfielders.
David Luiz partnered Branislav Ivanovic in central defence.
West Brom, without on-loan Romelu Lukaku, were able to pass Shane Long fit to play as a lone striker. Their defence was unchanged but they drafted in Graham Dorrans and and Marc-Antoine Fortune to play wide in a 4-2-3-1 shape, mirroring Chelsea and a change from their recent 4-4-2.
With Tottenham having gone ahead of Chelsea in the table last weekend and the north London derby to come on Sunday afternoon, this game at the Bridge was all about winning the three points to put added pressure on Spurs and Arsenal ahead of that clash.
Oscar could, and probably should have put the Blues in front with just three minutes played, the chance made by an exquisite ball by Ba who had taken possession out wide and passed low and out of reach of West Brom's retreating central defence. It came to Oscar just eight yards out but his first-time stab was pushed wide by Ben Foster.
Mata shot across the face of goal and wide moments later before West Brom counter-punched with a Steven Reid free-kick, arrowed past the Chelsea defensive wall. Cech had taken up the correct position and tipped it over the bar.
With 15 minutes played, Oscar was again found on the edge of the six-yard box and in a central position, this time by a Mata cross after Ramires had made in-roads with a run through the middle. The Brazilian's header was straight at Foster. The mask-free Ba was next to find the West Brom keeper's hands, with a skidding shot.
Chelsea were pushing hard for an opener and Hazard, scorer of an important goal in the previous outing at the Bridge, was the player who looked most on his game, frequently coming deep or switching wings to get the team playing.
West Brom were limited in their ambition at this stage of the contest but their many bodies back could not prevent Chelsea having a shot on goal when Yacob fouled Oscar. David Luiz took the free-kick and it was made harder for Foster when it deflected up off the wall, but the former England keeper made it to the top corner to claw the ball wide.
From the corner that followed, the Blues opened the scoring. Oscar and Lampard combined to send a cross to the far post where David Luiz did well to head down and back to Ba. From six yards out the Senegalese swept the ball home. There were 27 minutes played.
Demba Ba scores
Mata went close soon after and then Oscar sweetly half-volleyed a Mata corner. It looked net-bound until a West Brom leg kicked it wide. Oscar wasn't having the luck in front of goal. He and Azpilicueta had further shots blocked.
Chelsea had been well on top but would have liked more than a single-goal lead to take into the dressing room at the break to reflect that balance of play. Fortune's strong running down the right had caused some difficulties for the home team on odd occasions but the early free-kick apart, Cech had been largely untroubled.
There was decent applause for the players for their first-half performance as they went down the tunnel, but a hobbling Ramires was assisted by the medical staff as he made the journey.
Ramires recovered during the interval and took his place among two unchanged sides at the kick-off.
The wait for the 200th Lampard goal continued. Mata ran offside before squaring a Hazard pass to Lamps to find the net early in the half and then the captain on the day hit a free-kick into the wall.
Hazard was the game's first booked player for a late challenge near the corner flag. Chelsea had the Baggies penned well back.
Hazard later believed he should have had a penalty when he and Olsson collided in the area. It was side-to-side contact and the ref waved play on.
Hazard is fouled against West Brom
There was an hour played and time was becoming an increasing concern for the trailing visitors. Steve Clarke made his first change - Peter Odemwingie coming on for Fortune.
A foul was given for a challenge on Hazard by McAuley and it warranted a booking. This was wide outside the area however and the free-kick was cleared.
David Luiz took his turn to fire a free-kick into the wall before, on 77 minutes, yet another instalment of the dual between Oscar and Foster ended in the keeper's favour. Azpilicueta had sent over a speculative cross that Ba headed down well, but the shot from the no.11 was too straight.
Moses came on for Hazard soon after, the first Chelsea change, but before the substitute touched the ball, Oscar collected a throw and turned and wriggled into enough space to properly test Foster with an angled shot. This time it needed a diving stop to deny the Chelsea midfielder.
The value of the insurance of a second goal was emphasised when the best was brought out of Cech twice in a minute; the first time from an Odemwingie free-kick and then from close-range by a deflection off Azpilicueta as he tried to defend a corner.
Frank Lampard in action against West Brom
Lampard volleyed well over as that goal proved beyond the Blues and as we survived four minutes added time there were some strong defensive headers inside our area. Cech was asked to save one more low shot before Demba Ba's first goal since mid-January proved enough to win the three points.
Chelsea (4-2-3-1): Cech; Azpilicueta, Ivanovic, David Luiz, Cole; Ramires, Lampard (c); Hazard (Moses 80), Mata (Mikel 90+4), Oscar; Ba (Torres 87).
Unused subs Turnbull, Cahill, Terry, Bertrand.
Scorer Ba 28
Booked Hazard 55.
West Brom (4-2-3-1): Foster; Reid, McAuley, Olsson (c), Ridgewell; Mulumbu, Yacob (Rosenberg 82); Fortune (Odemwingie 61), Morrison, Dorrans (Thomas 70); Long.
Unused subs: Myhill, Jones, Tamas, Brown.
Booked McAuley 64, Odemwingie 84.
Referee Kevin Friend.