diff --git a/src/readable/byob_reader.rs b/src/readable/byob_reader.rs
index 473f00b..61c1e0e 100644
--- a/src/readable/byob_reader.rs
+++ b/src/readable/byob_reader.rs
@@ -179,8 +179,10 @@ impl<'stream> ReadableStreamBYOBReader<'stream> {
     /// return an error and leave the reader locked to the stream.
     #[inline]
     pub fn try_release_lock(self) -> Result<(), (js_sys::Error, Self)> {
-        self.as_raw().release_lock();
-        Ok(())
+        self.as_raw()
+            .unchecked_ref::<sys::ReadableStreamReaderExt>()
+            .try_release_lock()
+            .map_err(|err| (err, self))
     }
 
     /// Converts this `ReadableStreamBYOBReader` into an [`AsyncRead`].
diff --git a/src/readable/default_reader.rs b/src/readable/default_reader.rs
index 4d4e696..21ab949 100644
--- a/src/readable/default_reader.rs
+++ b/src/readable/default_reader.rs
@@ -112,8 +112,10 @@ impl<'stream> ReadableStreamDefaultReader<'stream> {
     /// return an error and leave the reader locked to the stream.
     #[inline]
     pub fn try_release_lock(self) -> Result<(), (js_sys::Error, Self)> {
-        self.as_raw().release_lock();
-        Ok(())
+        self.as_raw()
+            .unchecked_ref::<sys::ReadableStreamReaderExt>()
+            .try_release_lock()
+            .map_err(|err| (err, self))
     }
 
     /// Converts this `ReadableStreamDefaultReader` into a [`Stream`].
diff --git a/src/readable/sys.rs b/src/readable/sys.rs
index 62078d4..23b0968 100644
--- a/src/readable/sys.rs
+++ b/src/readable/sys.rs
@@ -29,6 +29,16 @@ extern "C" {
     ) -> Result<Object, Error>;
 }
 
+#[wasm_bindgen]
+extern "C" {
+    /// Additional methods for [`ReadableStreamDefaultReader`](web_sys::ReadableStreamDefaultReader)
+    /// and [`ReadableStreamByobReader`](web_sys::ReadableStreamByobReader).
+    pub(crate) type ReadableStreamReaderExt;
+
+    #[wasm_bindgen(method, catch, js_name = releaseLock)]
+    pub(crate) fn try_release_lock(this: &ReadableStreamReaderExt) -> Result<(), Error>;
+}
+
 #[wasm_bindgen]
 extern "C" {
     /// A result returned by [`ReadableStreamDefaultReader.read`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultReader/read).