diff --git a/tests/test_api.py b/tests/test_api.py
index 6dbf942015..26500c6532 100755
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -546,7 +546,7 @@ def test_metadata_targets(self):
             targets.signed.targets[filename].to_dict(), fileinfo.to_dict()
         )
         # Update an already existing fileinfo
-        targets.signed.update(filename, fileinfo)
+        targets.signed.update(fileinfo)
         # Verify that data is updated
         self.assertEqual(
             targets.signed.targets[filename].to_dict(), fileinfo.to_dict()
diff --git a/tuf/api/metadata.py b/tuf/api/metadata.py
index 2ddd1869d2..7250041997 100644
--- a/tuf/api/metadata.py
+++ b/tuf/api/metadata.py
@@ -1232,6 +1232,6 @@ def to_dict(self) -> Dict[str, Any]:
         return targets_dict
 
     # Modification.
-    def update(self, filename: str, fileinfo: TargetFile) -> None:
+    def update(self, fileinfo: TargetFile) -> None:
         """Assigns passed target file info to meta dict."""
-        self.targets[filename] = fileinfo
+        self.targets[fileinfo.path] = fileinfo