The Blues could have gone four points clear of second-placed Arsenal and five ahead of third-placed Manchester City and it appeared as it could have gone that way until the Baggies intervened in the 87th minute.
Branislav Ivanovic, who scored the winner at Manchester City last Monday, gave Chelsea the lead on the stroke of half-time when he got loose at a corner and slotted home David Luiz's flick-on from Willian's corner.
Pepe Mel's Baggies outfit did everything they could throughout the contest to frustrate Jose Mourinho's league leaders and the game plan was vindicated as they secured a much-needed point which saw them slip out of the relegation zone.
2013/14 Barclays Premier League season scores
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