diff --git a/src/calibre/gui2/store/search/models.py b/src/calibre/gui2/store/search/models.py
index 0ca3b5a2de..b1ccd0e40b 100644
--- a/src/calibre/gui2/store/search/models.py
+++ b/src/calibre/gui2/store/search/models.py
@@ -451,6 +451,7 @@ class SearchFilter(SearchQueryParser):
                     elif locvalue in ('author2', 'title2'):
                         m = self.IN_MATCH
                         vals = re.sub(r'(^|\s)(and|not|or|a|the|is|of|,)(\s|$)', ' ', accessor(sr)).split(' ')
+                        query = query.lower()
                     else:
                         vals = [accessor(sr)]
                     if self._match(query, vals, m):