BETHESDA (AFP) - The world's top three players struggled in the first round of the 111th US Open at Congressional Country club here on Thursday while lesser lights set the pace. World No.1 Luke Donald, No.2 Lee Westwood and No.3 Martin Kaymer all opened solidly enough at the devlish par-three 10th. But, playing in the same grouping, they were all soon in trouble, especially Englishman Donald, who dropped six stroke in six holes from the 13th. He battled back with a birdie at the first, his 10th hole, but was three-over through 14 holes. Germany's Kaymer, who has struggled for form since the Masters in April, fared no better, going out in one-over par 36 and then dropping strokes at the first and third to also stand at three over. Westwood was also out in 36, and a birdie at the second brought him to level par, but bogeys at the third and fourth set him back at two over. The early lead in the clubhouse at one-under 70, went to unheralded American qualifier Chez Reavie, who was in the first grouping out in the morning from the first tee. Out on the course, Ryan Palmer of the United States was three under through 11 holes with Sweden's Johan Edfors two under through 13 holes and American Jeff Overton level with him through 12. For the first time since he made his debut as an amateur in 1995, there was no Tiger Woods at the US Open, serious knee and tendon injuries sustained at the Masters in April having ruled him out this time around. His tumble down the world rankings ushered in a period of uncertainty at the top, with three players - Westwood, Kaymer and Donald - all taking turns to rule the roost in the last seven months. The sentimental favourite this week among many golf fans was 41-year-old Phil Mickelson who has endured more than his fair share of US Open heartbreak, having finished second a record five times in the tournament he most wants to win. Mickelson will head out in the afternoon in the company of emerging American talent Dustin Johnson and 22-year-old Ulsterman Rory McIlroy, who will be out to banish memories of his closing 80 at the Masters in April after leading by four going into the final round. In a packed international field of 156 golfers, US Golf Association officials have strung together some eye-catching groupings such as the all-Italian line-up of the Molinari brothers, Francesco and Edoardo, along with 18-year-old prodigy Matteo Manassero and Spaniards Sergio Garcia, Miguel Angel Jimenez and Alvaro Quiros. Then there are recent Masters winners Charl Schwartzel and Trevor Immelman of South Africa and Zach Johnson of the United States as well as defending champion Graeme McDowell with British Open champion Louis Oosthuizen and US amateur champion Peter Uihlein. The par-71 Blue course at Congressional, west of Washington, has been extensively remodeled since Ernie Els won the last time it was played here in 1997 and the consensus verdict is "tough but fair."