diff --git a/ui/jquery.ui.autocomplete.js b/ui/jquery.ui.autocomplete.js
index 940d41adfd..6b19c44016 100644
--- a/ui/jquery.ui.autocomplete.js
+++ b/ui/jquery.ui.autocomplete.js
@@ -210,7 +210,8 @@ $.widget( "ui.autocomplete", {
 	},
 
 	_initSource: function() {
-		var array,
+		var self = this,
+			array,
 			url;
 		if ( $.isArray(this.options.source) ) {
 			array = this.options.source;
@@ -220,7 +221,11 @@ $.widget( "ui.autocomplete", {
 		} else if ( typeof this.options.source === "string" ) {
 			url = this.options.source;
 			this.source = function( request, response ) {
-				$.getJSON( url, request, response );
+				self.xhr = $.getJSON( url, request, function( data, status, xhr ) {
+					if ( xhr === self.xhr ) {
+						response.apply( this, arguments );
+					}
+				});
 			};
 		} else {
 			this.source = this.options.source;