$json = '{"str": "\u0418\u0432\u0430\u043d\u043e\u0432"}';
$obj = json_decode($json);
print_r($obj);
As of PHP 5.4 it is possible to array dereference the result of a function or method call directly. Before it was only possible using a temporary variable.
As of PHP 5.5 it is possible to array dereference an array literal.