Global full text search with field match

I’m constructing a global full text search using the Content Delivery API.

Entries have a bunch of text fields, and also a field that specifies one or more tags.

My global full text search query works perfectly if I provide the query value only, but I want to narrow down the full text search to only search records with a specific tag, but still across all fields (so, [match] is not a good option for me). However, if I additionally provide a fields.tag[in] value, along with query, then nothing is returned.

(If I provide fields.tag[in] alone, without query, then of course all entries matching the specified tag are returned, so that aspect is definitely working!)

Is this possible to achieve in a single API call? If not, how should it be done, then?