Colorado Springs, Colo. - Greg Norman has been doing some globe-trotting of late, honeymooning with new wife Chris Evert, contending in the British Open and British Senior Open.

So it might be understandable if 18 holes of golf at 6,000 feet of altitude, in 96-degree heat and some

After taking 34 putts Thursday, Greg Norman said he had to revert to reading the greens, and not slopes, differently. (John Mummert/USGA)

residual jet lag, might take something out of the 53-year-old "Shark." And after opening the U.S. Senior Open at The Broadmoor on Thursday with a par 70, Norman acknowledged he was dragging a bit.

But it wasn't physical exhaustion he was dealing with, it was mental fatigue. Figuring out what club to hit and how hard to hit it in the thin mountain air is messing with Norman's noggin.

"It's still a mental brain drain by the time you do your calculations and try to figure out whether it's do percent or 30 percent or 18 percent," said Norman, referring to the percentages of distance to compensate for how much farther the ball carries in the altitude.

He added: "And by the time you do the math in your head, then you have to figure out what shot to hit. It's a brain drain and you really have to stay with it. Then whatever calculations you do make, you have to trust it."

The trust factor is critical, Norman said. There is precious margin for miscalculations at The Broadmoor. The dramatic contours in the greens, and the speed of the surfaces, makes missing a green a veritable death sentence where par is concerned.

"Four or 5 yards out is a lot out here," said Norman. "Sometimes, you can misjudge it by 4 or 5 yards and have to chip it four or five yards down the hole, which is near impossible."

Norman, playing in his second Senior Open, first since finishing fourth at the 2005 event, did an admirable job with the brainstorming. He hit 16 of 18 of his short-grass targets, numbers to make any rifle marksman proud. Norman also landed on 11 of 14 fairways.

But he needed 34 putts to make it back to the clubhouse, including three-putt bogeys on both Nos. 10 and 15. He offset three bogeys with three birdies during the day. That said, Norman wasn't accepting all of the blame for the faulty flat stick. As much trouble he had calculating distance, he had even more trouble finding a feel for the greens.

"The greens were very inconsistent," said Norman. "Some were very mushy, very soft. They put a lot of moisture in some greens and not in some others. It was tough judging ... It got into a bit of a guessing game at the end of the day."

That said, Norman's guess is everybody is going to miss some short putts this week. "These greens are huge greens, and got a lot of slope to them, a lot of grain," Norman said. "You know, you're going to have a lot of 3-, 4- and 5-footers, and you're not going to make them all. I had three three-putts and hopefully I don't have anymore. Maybe I've had them all in one day."

In the end, Norman's opening round of 70 at The Broadmoor did not create nearly the buzz of his opening-round 70 at Royal Birkdale two weeks ago - which put him atop the British Open leaderboard.

But at five strokes off the pace with 54 holes to play, the Shark is definitely a threat.

Phillip Howley is a freelance writer whose work previously has appeared on www.ussenioropen.com.