Irishmen Darren Clarke and Peter Lawrie, and David Howell of England shared the lead Friday after two rounds of the Dunhill Links Championship.
All three shot 4-under-par 68s to go 9-under for the two rounds.
Clarke carded his score on The Old Course at St. Andrews. Howell and Lawrie played Kingsbarns. Carnoustie is the third course being used in the unusual four-round event in Scotland.
A group of four were one shot behind -- Irishman Gary Murphy, former British Open winner Paul Lawrie, New Zealand's Michael Campbell and Henrik Bjornstad of Norway.
Ernie Els, the leader of the European Order of Merit just ahead of Clarke, bounced back from a level-par opening round to shoot a 7-under-par 65 on The Old Course.
Also at 7-under are Thai-based Scotsman Simon Yates and Soren Hansen of Denmark. Vijay Singh, leader of the US Tour money list, shot 66 at St. Andrews to put himself into contention at 6-under overall. US PGA champion Shaun Micheel had a 69 on The Old Course and is 2-under, tied for 54th place.
Clarke, who began his round at the 10th, birdied three of his first eight holes. But at the ninth, his drive finished in the Valley of Sin, a deep gully that fronts the famous finishing green.
His first shot with the putter barely made it up the hill, stopped, then rolled back down. His next effort finished 8m from the pin, and he two-putted for a bogey.
"I was thinking three, not five," said Clarke, adding that poor putting in the second round cost him at least three shots.
Peter Lawrie, a strong candidate for rookie of the year on the European Tour, missed the halfway cut in his last four tournaments following a good start.
"It would be a lovely bonus to be the top rookie, but I don't want to get ahead of myself. I've had an alignment problem in recent weeks, which I've had before," he said.
Howell has played well the last month since returning from a shoulder injury.
"It's probably the most consistent month's form I've ever had," said Howell.
Campbell, the Irish Open champion, missed an 18-inch putt at the first hole of The Old Course, then bogeyed the next hole before recovering on the back nine.