diff --git a/futures-util/src/stream/stream/split.rs b/futures-util/src/stream/stream/split.rs
index 28d7aa71a0..4118b33462 100644
--- a/futures-util/src/stream/stream/split.rs
+++ b/futures-util/src/stream/stream/split.rs
@@ -61,6 +61,23 @@ impl<S: Sink<Item> + Unpin, Item> SplitSink<S, Item> {
     }
 }
 
+impl<S: Sink<Item>, Item> SplitSink<S, Item> {
+    fn poll_flush_slot(mut inner: Pin<&mut S>, slot: &mut Option<Item>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
+        if slot.is_some() {
+            ready!(inner.as_mut().poll_ready(cx))?;
+            Poll::Ready(inner.start_send(slot.take().unwrap()))
+        } else {
+            Poll::Ready(Ok(()))
+        }
+    }
+
+    fn poll_lock_and_flush_slot(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
+        let this = &mut *self;
+        let mut inner = ready!(this.lock.poll_lock(cx));
+        Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx)
+    }
+}
+
 impl<S: Sink<Item>, Item> Sink<Item> for SplitSink<S, Item> {
     type Error = S::Error;
 
@@ -69,7 +86,7 @@ impl<S: Sink<Item>, Item> Sink<Item> for SplitSink<S, Item> {
             if self.slot.is_none() {
                 return Poll::Ready(Ok(()));
             }
-            ready!(self.as_mut().poll_flush(cx))?;
+            ready!(self.as_mut().poll_lock_and_flush_slot(cx))?;
         }
     }
 
@@ -81,20 +98,14 @@ impl<S: Sink<Item>, Item> Sink<Item> for SplitSink<S, Item> {
     fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
         let this = &mut *self;
         let mut inner = ready!(this.lock.poll_lock(cx));
-        if this.slot.is_some() {
-            ready!(inner.as_pin_mut().poll_ready(cx))?;
-            inner.as_pin_mut().start_send(this.slot.take().unwrap())?;
-        }
+        ready!(Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx))?;
         inner.as_pin_mut().poll_flush(cx)
     }
 
     fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
         let this = &mut *self;
         let mut inner = ready!(this.lock.poll_lock(cx));
-        if this.slot.is_some() {
-            ready!(inner.as_pin_mut().poll_ready(cx))?;
-            inner.as_pin_mut().start_send(this.slot.take().unwrap())?
-        }
+        ready!(Self::poll_flush_slot(inner.as_pin_mut(), &mut this.slot, cx))?;
         inner.as_pin_mut().poll_close(cx)
     }
 }