But the biggest surprises were right behind him, starting with a pair of British Open champions who once were No. 1 in the world.
Norman barely touched a club in the month leading up to his 26th appearance in golf's oldest championship. The 53-year-old married tennis great Chris Evert three weeks ago, and a trip to England counts as the tail end of his honeymoon.
He wound up renewing his love affair with links golf, delivering great escapes over his final three holes for an even-par 70 that put his name atop the leaderboard for most of the afternoon until Choi birdied the final two holes.
Choi was at 1-under 139, one shot ahead of Norman.
"My expectations were almost nil coming in, to tell you the truth," Norman said. "My expectations are still realistically low, and I have to be that way. I can't sit here and say,
'OK, it's great. I'm playing well and I'm doing it.' I am playing well. I am doing it. But I still haven't been there for a long time."
His last victory was 10 years ago in Australia at the Greg Norman Holden International. He hasn't been this close to the lead at the halfway point of a major since he was leading the
'96 Masters.
Duval knows that feeling.
His last victory was the Dunlop Phoenix in Japan at the end of 2001, the year he won his only major at Royal Lytham & St. Annes. What followed was a mysterious slump that included a half-dozen coaches, precious few rounds under par and an aloof player who found happiness in marriage and children.
For those waiting for another collapse, Duval never showed a hint of it.
He chipped in for birdie at No. 11, kept damage to only a bogey when he found a pot bunker off the tee on the 13th, and bounced back with another birdie on the par-3 14th.
"I've been working toward greatness, not just getting back to making cuts and managing to play halfway decent," said Duval, who had made only one cut in 11 starts this year before arriving at Royal Birkdale. "I've been trying to take the long route and the hard route and try to get back to greatness.
"That story is yet to be told as to whether I can get back to that point or not," he said. "But that's what I strive for."
This wonderful story unfolding at Birkdale still has a long way to go.
It starts with Choi, a 37-year-old from South Korea who didn't think much of golf until a high school teacher handed him an instructional book by Jack Nicklaus. A seven-time winner on the PGA Tour
- the most of any Asian player - he overcame a bogey on the first hole to play flawlessly in a steady 20 mph wind and occasional squirts of rain.
"I think today was probably my best round I've ever played at the British Open," said Choi, who trailed Sergio Garcia by two shots going into the third round at Carnoustie last year before finishing in a tie for eighth. "Everything worked the way I wanted it to."
The best finish belonged to Camilo Villegas of Colombia, whose lone victory came last year in Japan.
A marketing dream, Villegas is known as "Spider-Man" for splaying his body horizontally to read putts at surface level. He made everything over the final five holes
- all birdies - for a tournament-best 65 that left him two shots behind.
"Let me tell you, when you get on the first tee, you never think about a score," said Villegas, who got into the British Open as an alternate when Kenny Perry decided not to come. "You just think about every single shot because you don't know how bad it can get, when the weather is going to get like it was yesterday morning. So you're just trying to grind every single shot. And that's what I did."
