diff --git a/index.js b/index.js
index b10acfb..38cfc1a 100644
--- a/index.js
+++ b/index.js
@@ -116,7 +116,7 @@ module.exports = function (schema, options) {
               if (model.baseModelName && indexOptions.partialFilterExpression === null) {
                 model = model.db.model(model.baseModelName);
               }
-              conditions = {$and: [conditions, indexOptions.partialFilterExpression || {}]};
+              conditions = {...indexOptions.partialFilterExpression, ...conditions};
 
               const count = await model.find(conditions).countDocuments();
               return count === 0;
diff --git a/package.json b/package.json
index 9c021d6..680d510 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mongoose-unique-validator",
-  "version": "3.0.0",
+  "version": "3.0.1",
   "description": "mongoose-unique-validator is a plugin which adds pre-save validation for unique fields within a Mongoose schema.",
   "main": "index.js",
   "scripts": {