diff --git a/src/wp-admin/includes/meta-boxes.php b/src/wp-admin/includes/meta-boxes.php
index 4584fff555..95513ae74e 100644
--- a/src/wp-admin/includes/meta-boxes.php
+++ b/src/wp-admin/includes/meta-boxes.php
@@ -1437,14 +1437,14 @@ function register_and_do_post_meta_boxes( $post ) {
 
 	$publish_callback_args = array( '__back_compat_meta_box' => true );
 	if ( post_type_supports( $post_type, 'revisions' ) && 'auto-draft' !== $post->post_status ) {
-		$revisions = wp_get_post_revisions( $post->ID );
+		$revisions = wp_get_post_revisions( $post->ID, array( 'fields' => 'ids' ) );
 
 		// We should aim to show the revisions meta box only when there are revisions.
 		if ( count( $revisions ) > 1 ) {
 			reset( $revisions ); // Reset pointer for key().
 			$publish_callback_args = array(
 				'revisions_count'        => count( $revisions ),
-				'revision_id'            => key( $revisions ),
+				'revision_id'            => array_shift( $revisions ),
 				'__back_compat_meta_box' => true,
 			);
 			add_meta_box( 'revisionsdiv', __( 'Revisions' ), 'post_revisions_meta_box', null, 'normal', 'core', array( '__back_compat_meta_box' => true ) );
diff --git a/src/wp-includes/revision.php b/src/wp-includes/revision.php
index 9eb74b98a9..119bef816b 100644
--- a/src/wp-includes/revision.php
+++ b/src/wp-includes/revision.php
@@ -221,7 +221,7 @@ function wp_save_post_revision( $post_id ) {
 /**
  * Retrieve the autosaved data of the specified post.
  *
- * Returns a post object containing the information that was autosaved for the
+ * Returns an object containing the information that was autosaved for the
  * specified post. If the optional $user_id is passed, returns the autosave for that user
  * otherwise returns the latest autosave.
  *
@@ -232,19 +232,35 @@ function wp_save_post_revision( $post_id ) {
  * @return WP_Post|false The autosaved data or false on failure or when no autosave exists.
  */
 function wp_get_post_autosave( $post_id, $user_id = 0 ) {
-	$revisions = wp_get_post_revisions( $post_id, array( 'check_enabled' => false ) );
+	global $wpdb;
 
-	foreach ( $revisions as $revision ) {
-		if ( false !== strpos( $revision->post_name, "{$post_id}-autosave" ) ) {
-			if ( $user_id && $user_id != $revision->post_author ) {
-				continue;
-			}
+	$autosave_name = $post_id . '-autosave-v1';
+	$user_id_query = ( 0 !== $user_id ) ? "AND post_author = $user_id" : null;
 
-			return $revision;
-		}
+	// Construct the autosave query
+	$autosave_query = "
+		SELECT *
+		FROM $wpdb->posts
+		WHERE post_parent = %d
+		AND post_type = 'revision'
+		AND post_status = 'inherit'
+		AND post_name   = %s " . $user_id_query . '
+		ORDER BY post_date DESC
+		LIMIT 1';
+
+	$autosave = $wpdb->get_results(
+		$wpdb->prepare(
+			$autosave_query,
+			$post_id,
+			$autosave_name
+		)
+	);
+
+	if ( ! $autosave ) {
+		return false;
 	}
 
-	return false;
+	return $autosave[0];
 }
 
 /**
diff --git a/tests/phpunit/tests/ajax/CustomizeManager.php b/tests/phpunit/tests/ajax/CustomizeManager.php
index 1126e8e667..1ed20de31f 100644
--- a/tests/phpunit/tests/ajax/CustomizeManager.php
+++ b/tests/phpunit/tests/ajax/CustomizeManager.php
@@ -472,7 +472,7 @@ class Tests_Ajax_CustomizeManager extends WP_Ajax_UnitTestCase {
 		$this->assertTrue( $this->_last_response_parsed['success'] );
 		$this->assertEquals( 'draft', $this->_last_response_parsed['data']['changeset_status'] );
 		$autosave_revision = wp_get_post_autosave( $post_id );
-		$this->assertInstanceOf( 'WP_Post', $autosave_revision );
+		$this->assertInstanceOf( 'stdClass', $autosave_revision );
 
 		$this->assertContains( 'New Site Title', get_post( $post_id )->post_content );
 		$this->assertContains( 'Autosaved Site Title', $autosave_revision->post_content );
@@ -699,7 +699,7 @@ class Tests_Ajax_CustomizeManager extends WP_Ajax_UnitTestCase {
 		);
 		$this->assertNotWPError( $r );
 		$autosave_revision = wp_get_post_autosave( $wp_customize->changeset_post_id() );
-		$this->assertInstanceOf( 'WP_Post', $autosave_revision );
+		$this->assertInstanceOf( 'stdClass', $autosave_revision );
 		$this->assertContains( 'Foo', get_post( $wp_customize->changeset_post_id() )->post_content );
 		$this->assertContains( 'Bar', $autosave_revision->post_content );
 
diff --git a/tests/phpunit/tests/customize/manager.php b/tests/phpunit/tests/customize/manager.php
index 00dcd333c6..dda069dfc1 100644
--- a/tests/phpunit/tests/customize/manager.php
+++ b/tests/phpunit/tests/customize/manager.php
@@ -1891,7 +1891,7 @@ class Tests_WP_Customize_Manager extends WP_UnitTestCase {
 
 		// Verify that autosave happened.
 		$autosave_revision = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
-		$this->assertInstanceOf( 'WP_Post', $autosave_revision );
+		$this->assertInstanceOf( 'stdClass', $autosave_revision );
 		$this->assertContains( 'Draft Title', get_post( $changeset_post_id )->post_content );
 		$this->assertContains( 'Autosave Title', $autosave_revision->post_content );
 	}