"For the club to expect to do only as well as last year is unacceptable," he told the Sunday Times. "If you run a large plc and you tell your shareholders you will do the same next year, they get pretty disappointed.
Sir Keith, a nonexecutive director at White Hart Lane, also blamed the press for damaging the club's image.
He said: "The media has done a disservice to the club in misreporting an enormous amount of what has been going on, because 90% of it is garbage. The speculation that the club would consider making changes after two games is rubbish. What I have read is not remotely close to the briefings I have had.
"Managers, players and chief executives are only as good as their performance. I've been involved in lots of sports. If my America's Cup skipper or chief executive, for instance, doesn't do the business, we change."