diff --git a/scrapy/extensions/feedexport.py b/scrapy/extensions/feedexport.py
index cd26b5778..da1a88299 100644
--- a/scrapy/extensions/feedexport.py
+++ b/scrapy/extensions/feedexport.py
@@ -383,13 +383,20 @@ class FeedExporter:
         return defer.DeferredList(deferred_list) if deferred_list else None
 
     def _close_slot(self, slot, spider):
+        def get_file(slot_):
+            if isinstance(slot_.file, PostProcessingManager):
+                slot_.file.close()
+                return slot_.file.file
+            return slot_.file
+
         slot.finish_exporting()
         if not slot.itemcount and not slot.store_empty:
             # We need to call slot.storage.store nonetheless to get the file
             # properly closed.
-            return defer.maybeDeferred(slot.storage.store, slot.file)
+            return defer.maybeDeferred(slot.storage.store, get_file(slot))
+
         logmsg = f"{slot.format} feed ({slot.itemcount} items) in: {slot.uri}"
-        d = defer.maybeDeferred(slot.storage.store, slot.file)
+        d = defer.maybeDeferred(slot.storage.store, get_file(slot))
 
         d.addCallback(
             self._handle_store_success, logmsg, spider, type(slot.storage).__name__
diff --git a/tests/test_feedexport.py b/tests/test_feedexport.py
index eafe1b334..3124d9d67 100644
--- a/tests/test_feedexport.py
+++ b/tests/test_feedexport.py
@@ -1638,6 +1638,57 @@ class FeedExportTest(FeedExportTestBase):
             data = yield self.exported_data(items, settings)
             self.assertEqual(row["expected"], data[feed_options["format"]])
 
+    @defer.inlineCallbacks
+    def test_storage_file_no_postprocessing(self):
+        @implementer(IFeedStorage)
+        class Storage:
+            def __init__(self, uri, *, feed_options=None):
+                pass
+
+            def open(self, spider):
+                Storage.open_file = tempfile.NamedTemporaryFile(prefix="feed-")
+                return Storage.open_file
+
+            def store(self, file):
+                Storage.store_file = file
+                file.close()
+
+        settings = {
+            "FEEDS": {self._random_temp_filename(): {"format": "jsonlines"}},
+            "FEED_STORAGES": {"file": Storage},
+        }
+        yield self.exported_no_data(settings)
+        self.assertIs(Storage.open_file, Storage.store_file)
+
+    @defer.inlineCallbacks
+    def test_storage_file_postprocessing(self):
+        @implementer(IFeedStorage)
+        class Storage:
+            def __init__(self, uri, *, feed_options=None):
+                pass
+
+            def open(self, spider):
+                Storage.open_file = tempfile.NamedTemporaryFile(prefix="feed-")
+                return Storage.open_file
+
+            def store(self, file):
+                Storage.store_file = file
+                file.close()
+
+        settings = {
+            "FEEDS": {
+                self._random_temp_filename(): {
+                    "format": "jsonlines",
+                    "postprocessing": [
+                        "scrapy.extensions.postprocessing.GzipPlugin",
+                    ],
+                },
+            },
+            "FEED_STORAGES": {"file": Storage},
+        }
+        yield self.exported_no_data(settings)
+        self.assertIs(Storage.open_file, Storage.store_file)
+
 
 class FeedPostProcessedExportsTest(FeedExportTestBase):
     __test__ = True