A month ago the Albion game might have been deemed a straightforward assignment but things have taken a turn for the worse following a bright start to the season, with three defeats in a row at the hands of Arsenal, Wolves and Lech Poznan.
All of which means West Brom is now a major match in its own right.
"The Manchester derby is coming up but right now the most important match is West Brom," said Zabaleta.
"We must keep our focus on that, because we really need to win it.
"Sometimes you lose games but losing three in a row is not good because you lose confidence. Now we have to be positive. We have to be ready for West Brom and for the derby next week."