diff --git a/src/Internal/QueueState.php b/src/Internal/QueueState.php
index a7aed36..61c2d03 100644
--- a/src/Internal/QueueState.php
+++ b/src/Internal/QueueState.php
@@ -177,17 +177,18 @@ public function hasPending(): bool
      */
     public function dispose(): void
     {
-        try {
-            if ($this->completed || $this->disposed) {
-                return; // Pipeline already completed or failed.
-            }
+        if ($this->disposed) {
+            return;
+        }
 
-            $this->finalize(new DisposedException, true);
-        } finally {
-            if ($this->disposed) {
-                $this->triggerDisposal();
-            }
+        if ($this->completed) {
+            $this->disposed = true;
+            $this->exception = new DisposedException;
+            $this->triggerDisposal();
+            return;
         }
+
+        $this->finalize(new DisposedException, true);
     }
 
     /**
diff --git a/test/QueueTest.php b/test/QueueTest.php
index f158e6f..8ebe47d 100644
--- a/test/QueueTest.php
+++ b/test/QueueTest.php
@@ -328,6 +328,32 @@ public function testFailWithDisposedException(): void
         $this->queue->complete();
     }
 
+    public function testBackpressureRelievedAfterCompletionThenDisposal(): void
+    {
+        $emit1 = $this->queue->pushAsync(1);
+        $emit2 = $this->queue->pushAsync(2);
+
+        $pipeline = $this->queue->pipe()->getIterator();
+        $consume = async(function () use ($pipeline) {
+            $pipeline->continue();
+            return $pipeline->getValue();
+        });
+
+        $this->queue->complete();
+
+        self::assertSame(1, $consume->await());
+        $emit1->await();
+
+        $pipeline->dispose();
+        self::assertTrue($this->queue->isDisposed());
+
+        try {
+            $emit2->await();
+            $this->fail(\sprintf('Expected instance of %s to be thrown', DisposedException::class));
+        } catch (DisposedException) {
+        }
+    }
+
     public function testTraversable(): void
     {
         EventLoop::queue(function (): void {