Mario Stanic set Chelsea on the way to the win that lifted them into fourth place with a first-half header before Zola doubled their advantage with his 14th goal of the season ten minutes into the second half.
Chelsea did not really have to get out of first gear to see off the challenge of Albion whose margin of defeat would have been greater but for goalkeeper Russell Hoult.
Chelsea had threatened to score well before Stanic struck and only two smart saves by Hoult kept Albion on level terms.
Albion, who had lost both central defender Darren Moore and midfielder Derek McInnes through injury after a quarter of an hour, handed an opening to Jimmy Floyd Hasselbaink in the 23rd minute.
Hasselbaink took advantage of a mix-up between the Albion central defenders Sean Gregan and Larus Sigurdsson and homed in on goal.
But Hoult was more than equal to the task, throwing up his right hand to deflect Hasselbaink's shot over the bar.
Hoult then plucked a free-kick from Zola out of the air before Chelsea's pressure finally paid off after 38 minutes.
Albion were undone at a set piece when left-back Graeme Le Saux lifted over a corner. Stanic rose above the Albion defence to head home from just four yards.
Baggies boss Gary Megson threw caution to the wind at half time by sending on striker Danny Dichio in place of full-back Ifeanyi Udeze to form a three-man attack alongside Jason Roberts and Lee Hughes.
But their hopes of forcing their way back into the game were dashed ten minutes into the second-half when Zola struck.
Hasselbaink, who had again been denied by Hoult in the 49th minute, turned provider when he fed a neat pass into the path of Zola.
The little Italian made space for himself on the edge of the area before beating Hoult with a low right-foot drive to secure Chelsea's 14th win of the season.