Tiger Woods shot a superb round of 66 to take the lead at the WGC-American Express Championships in Atlanta.
The world number one moved to seven under par, five shots clear of Sergio Garcia, KJ Choi, Rocco Mediate and Tim Herron.
First-round leader Garcia had a disappointing day, shooting 73 to drop back to two under.
Darren Clarke had an even worse time with a disastrous round of 82 that left him 11 over par.
"You had to be so patient, and above all get the ball in the
fairway," admitted Woods after his round which included seven birdies.
"A lot of times you have to play away from the flags. It's fun to play a tournament where you have to play like this and it is nice to be in front," he said.
Clarke made seven bogeys and one double bogey on the outward nine, and managed just one birdie on the 13th.
"Wow, what a day," said Clarke afterwards.
ROUND TWO (US unless stated)
-7 Tiger Woods
-2 Sergio Garcia (Spa), KJ Choi (S Kor), Rocco Mediate, Tim Herron
"I couldn't have been a shot better. I gave every one 100%.
"I drove it poorly and hit the ball terribly. It came as a complete shock to the system.
"I can't remember the last time I played nine holes in 10 over, but I didn't go stomping about and it's not all bad. It has been a good last month."