Tiger Woods shares the halfway lead with fellow Americans Jim Furyk and David Toms in the 2012 US Open at Olympic.
Woods, who is looking to win a 15th major title, shot a second-round 70 on Friday, while 2003 champion Furyk carded 69, and 2001 US PGA winner Toms 70, to lead by one at one under par.
Woods picked up a shot at the third to take the lead, but went back down the leaderboard with three straight bogeys from the fifth.
However, he settled himself with two pars before birdies came at 10 and 13.
"It was really, really tough and I just had to stay as patient as possible," said the 36-year-old afterwards.
"I think I'm in a good spot. This tournament, you just keep plodding along.
"You're just playing for a lot of pars. This is not a tournament where we have to make a bunch of birdies."
-1 J Furyk (US), T Woods (US), D Toms (US)
+1 J Peterson (US), N Colsaerts (Bel), G McDowell (NI), M Thompson (US)