When Phil Mickelson tees off today in the first round of the British Open golf tournament in Carnoustie, on the east coast of Scotland, he will do so happy in the knowledge that he has had the best possible help in preparing for the competition.

At his side since April has been the formidable coach Butch Harmon, who previously spent several years working with the world's number one golfer Tiger Woods. Mickelson has been striving to achieve that extra 5 per cent of performance that could make the difference between success and failure come Sunday night.