When Luke Donald began his U.S. Open, he did so as the world’s top-ranked player, and he struck a shot that perfectly suited that status, a gorgeous 4-iron over the water at the 10th that settled four feet below the hole. His 4-iron approach at the dastardly par-4 11th again nestled in nicely, and again he made the putt. The No. 1 player in the world began his Open birdie-birdie, and his torrid streak looked like it would continue.

Yet when Donald made the turn, he did so at 4 over par. Nearly five hours later, he said the following: “It was a little bit discouraging that I didn’t play like I felt I could play.”

The marquee group on the first morning of the Open at Congressional Country Club featured Nos. 1, 2 and 3 in the world. At times, they played like Nos. 101, 102 and 103. Donald’s brilliant start turned into a grind of a 3-over 74. England’s Lee Westwood, a compatriot of Donald ranked second, struggled to a 75. Martin Kaymer, the German who’s ranked third, managed a 74.

Those scores, in a vacuum, aren’t that horrible at a U.S. Open, even from the players who are, ostensibly, the three best in the world. But consider the prism through which they viewed this Thursday, when they ended up well off Rory McIlroy’s lead of 6-under 65.

“It’s not a very good score, because I think the course is there for the taking,” Westwood said. “I just made too many mistakes.”

With Tiger Woods not only no longer ranked No. 1 — his span of five consecutive years at the top ended last October, and he has since plummeted to 15th — but also not at Congressional because of injury, the world rankings have become a moving target. Westwood initially took over for Woods, then handed off to Kaymer early this year, then took it back. Donald, playing the most consistent golf on the planet, moved to No. 1 with a playoff victory over Westwood last month in Europe.

All three raved about the grouping before hand. All three just needed to survive the day afterward.

“It’s always fun playing with guys who are friends,” Donald said. “But we obviously all three struggled a bit.”

Given his start and his play of late — he has two wins among his 10 straight top-10 finishes — Donald’s struggles were most perplexing. He gave his first shot back with a three-putt at 13, another back by missing a five-footer at 14, had to hit a 25-footer for par at 15, went through the green with his third at the par-5 16th for another bogey, then couldn’t get up-and-down from a bunker at the 17th. Add in a miserable 18th — his ninth hole of the day — in which he had to hack out of thick rough, then hit a poor wedge over the back of the green en route to double bogey, and the memory of that first, pure 4-iron faded.

“I made mistakes,” he said, “I usually wouldn’t make.”

Mistakes not normally associated with the world’s No. 1 — or 2 or 3 — player.