Having taken four points from a possible six in their first two qualifying games in Group G, a Zahavi-inspired Israel extended their unbeaten run with an excellent all-round performance in Riga.
Israel showed their superiority from kick-off and they forged ahead after nine minutes when Zahavi curled a stunning 25-yard free-kick into the top corner.
Zahavi was a threat throughout, stinging the fingers of the Lativa goalkeeper on 32 minutes after a well-worked short corner in a first half in which Israel were on the front foot.
Latvia improved in the second half, forcing Israel keeper Ariel Harush into two fine saves.
It was fitting the final word went to Zahavi, who completed the scoring with Israel's third on 80 minutes - his seventh in three qualifiers.
Israel take on group leaders Poland on Monday night.