diff --git a/dom/fetch/Request.cpp b/dom/fetch/Request.cpp
index dcc800fde7aa..fe65bf59ba0e 100644
--- a/dom/fetch/Request.cpp
+++ b/dom/fetch/Request.cpp
@@ -322,9 +322,11 @@ already_AddRefed<Request> Request::Constructor(const GlobalObject& aGlobal,
                                        ? aInit.mCredentials.Value()
                                        : fallbackCredentials;
 
-  if (mode == RequestMode::Navigate ||
-      (aInit.IsAnyMemberPresent() &&
-       request->Mode() == RequestMode::Navigate)) {
+  if (mode == RequestMode::Navigate) {
+    aRv.ThrowTypeError<MSG_INVALID_REQUEST_MODE>(NS_LITERAL_STRING("navigate"));
+    return nullptr;
+  }
+  if (aInit.IsAnyMemberPresent() && request->Mode() == RequestMode::Navigate) {
     mode = RequestMode::Same_origin;
   }
 
diff --git a/testing/web-platform/meta/fetch/api/request/request-error.html.ini b/testing/web-platform/meta/fetch/api/request/request-error.html.ini
index b8da81855247..b74d414a242d 100644
--- a/testing/web-platform/meta/fetch/api/request/request-error.html.ini
+++ b/testing/web-platform/meta/fetch/api/request/request-error.html.ini
@@ -2,9 +2,6 @@
   [RequestInit's window is not null]
     expected: FAIL
 
-  [RequestInit's mode is navigate]
-    expected: FAIL
-
   [RequestInit's mode is no-cors and integrity is not empty]
     expected: FAIL