Butch Harmon, the first golf coach to shape Tiger Woods' swing for the constant rigours of the professional game, has offered a ringing endorsement of the world No1's greatest rival, Phil Mickelson.

Though Woods is absent from the Open Championship at Royal Birkdale through injury, Harmon revealed that Mickelson is still driven by a fierce desire to become a better player than his fellow American.

Harmon, who stopped working with Woods some years ago, has now hooked up with Mickelson and is helping him try to add to his three major championships.

He said: "There were a couple of things I didn't know about Phil. Number one, I always thought he was lazy, but I've found out he works really hard. He's a joy to work with.

"He has worked very hard on his physical fitness this year, which he needed to do, and on the other things he wanted to do with his swing.

"The other thing is that even though I knew he was good, it turns out he is much better than I thought he was.

"You always thought of Phil Mickelson as a guy who had a great short game. He does have a great short game, but he also has a great variety of shots with every club. Plus, he is an unbelievable competitor.

"He wants to be the best he can be and he wants to beat Tiger Woods. I'm not sure a lot of guys out there feel that way."

In fact, it is probably just as well that Woods is not posing a challenge this week, because Mickelson will have enough on his plate meeting the demands of a typical Open links course.

The 38-year-old Californian has won two Masters titles and a US PGA Championship, in addition to being runner-up in the US Open four times.

But in the Open, apart from a third place showing at Troon in 2004, he has come nowhere.

Mickelson, second only to Woods in the rankings, admitted: "2004 was the first time I felt comfortable and confident playing golf over here.

"I had been working on taking some spin off of my short irons and it was that process that allowed me to control my trajectory, control my spin rate for the conditions here.

"If the wind blows as strong as it has been, the short game is going to be critical here."

And as Harmon pointed out, he has a great short game.