From Brian Keogh in Tulsa

John Daly took a massive gamble at the US PGA and hit the jack pot with a sensational opening 67 to grab the clubhouse lead.

The 1991 PGA champion didn't bother to play a practice round because it was too hot and spent the week playing the slot at the Cherokee Casino.

The last time Daly didn't play a practice round at the major was when he won at Crooked Stick in 1991, getting into the field as ninth alternate and driving through the night to reach the course.

Open champion Padraig Harrington cruised through the first ten holes in level par, wiping out a bogey at the par-five fifth with a 15 footer for birdie from the back fringe of the short par-four ninth.

But Paul McGinley was two over par after just six holes of his opening round as he racked up back-to-back bogeys at the 14th and 15th.

England's Graeme Storm lit up the tournament late in the afternoon as he went out in four under par 31 and then birdied the second to lead on the course on five under par.

But the real star of the day was Daly, who opted not to play a practice round because of the heat.

He said: "There was odds with all the caddies and players this week who would fall first, me or my caddie. So we made it. We made 18 holes.

"But, it was one of those rounds, I was very aggressive off the tee. I didn't know what else to do. I haven't played this course since '94. Didn't play a practice round this week because it was too hot."

Asked how he coped with the temperatures, he said: "I light up a cigarette and drink some caffeine and it actually works. It does bother me but I'm used to it, let's put it that way.

"When you grow up around this area it's not the heat that bothers you, it's more the humidity than anything.

"You can deal with heat. I can go to Palm Springs, California, Phoenix, Arizona, right now it could be 120 degrees and you hardly sweat. So humidity is brutal and we're used to it."

The Wild Thing, 41, has made just five cuts from 17 starts on the PGA Tour this season after losing his card last year.

But he showed he can still play as he racked up birdies at the fourth, seventh, ninth and 13th before dropping his only shot of the day at the 16th.

The key to his round was his amazing putting on the front nine - 12 putts in all and six single putts in a row.