diff --git a/Src/Modules/pcre.c b/Src/Modules/pcre.c
index e48ae3ae5..e4cdd8dbd 100644
--- a/Src/Modules/pcre.c
+++ b/Src/Modules/pcre.c
@@ -210,7 +210,8 @@ zpcre_get_substrings(pcre2_code *pat, char *arg, pcre2_match_data *mdata,
 	    }
 	    *x = NULL;
 	    setaparam(substravar, matches);
-	}
+	} else if (substravar)
+	    unsetparam(substravar);
 
 	if (namedassoc
 		&& !pcre2_pattern_info(pat, PCRE2_INFO_NAMECOUNT, &ncount) && ncount