Players began the first official practice rounds on Monday for this week's 111th US Open, some of them getting their first look at the event's trademark dense rough and lightning-fast greens.
New Zealand's Michael Campbell, the 2005 US Open champion, was the first man out on the par-71, 7,574-yard Congressional Country Club layout, testing the front nine 11 minutes before 7 in the morning in mild and sunny conditions.
Each player mixes practice needs with energy conservation in what figures to be a grueling week and a test of nerve and patience as well as skills.
"By Thursday I don't want to be overworked," American Hunter Mahan said. "I want to be very fresh mentally, physically and ready to go to battle, because the US Open is a battle and it is probably the longest four days of the year."
Much of the focus in Thursday's opening round at Congressional Country Club will be upon the trio of World No. 1 Luke Donald of England and the prior two No. 1s, England's Lee Westwood and Germany's Martin Kaymer.
The European stars tee off at 8:06 in the morning.
Donald sounded relaxed, joking late Sunday on his Twitter microblogging site that he was "Thinking of rocking up to the 1st tee on Thursday wearing a big ass pair of headphones, NBA style. What u think? Ha."
It probably would not help his chances of following England's Tony Jacklin in 1970 and Northern Ireland's Graeme McDowell last year as the only Europeans to win the US Open since 1925.
Donald and Westwood seek their first major titles while Kaymer made his major breakthrough by taking last year's PGA Championship.