diff --git a/lib/client-assets.php b/lib/client-assets.php
index 8c4a6bd373c040..64d4dd18d75deb 100644
--- a/lib/client-assets.php
+++ b/lib/client-assets.php
@@ -614,12 +614,6 @@ function gutenberg_extend_wp_api_backbone_client() {
 			wp_json_encode( $schema_response->get_data() )
 		), 'before' );
 	}
-
-	/*
-	 * For API requests to happen over HTTP/1.0 methods,
-	 * as HTTP/1.1 methods are blocked in a variety of situations.
-	 */
-	wp_add_inline_script( 'wp-api', 'Backbone.emulateHTTP = true;', 'before' );
 }
 
 /**
diff --git a/lib/compat.php b/lib/compat.php
index 6b4845d9a718fc..e0372a72fadabd 100644
--- a/lib/compat.php
+++ b/lib/compat.php
@@ -102,6 +102,37 @@ function gutenberg_shim_fix_api_request_plain_permalinks( $scripts ) {
 }
 add_action( 'wp_default_scripts', 'gutenberg_shim_fix_api_request_plain_permalinks' );
 
+/**
+ * Shims support for emulating HTTP/1.0 requests in wp.apiRequest
+ *
+ * @see https://core.trac.wordpress.org/ticket/43605
+ *
+ * @param WP_Scripts $scripts WP_Scripts instance (passed by reference).
+ */
+function gutenberg_shim_api_request_emulate_http( $scripts ) {
+	$api_request_fix = <<<JS
+( function( wp ) {
+	var oldApiRequest = wp.apiRequest;
+	wp.apiRequest = function ( options ) {
+		if ( options.method ) {
+			if ( [ 'PATCH', 'PUT', 'DELETE' ].indexOf( options.method.toUpperCase() ) >= 0 ) {
+				if ( ! options.headers ) {
+					options.headers = {};
+				}
+				options.headers['X-HTTP-Method-Override'] = options.method;
+				options.method = 'POST';
+			}
+		}
+
+		return oldApiRequest( options );
+	}
+} )( window.wp );
+JS;
+
+	$scripts->add_inline_script( 'wp-api-request', $api_request_fix, 'after' );
+}
+add_action( 'wp_default_scripts', 'gutenberg_shim_api_request_emulate_http' );
+
 /**
  * Disables wpautop behavior in classic editor when post contains blocks, to
  * prevent removep from invalidating paragraph blocks.