Dustin Johnson surged into a share of the lead with back-to-back birdies in Friday's second round of the Masters while Tiger Woods prepared to tee off on a difficult day at Augusta National.
Johnson opened with a five-under par 67 on Thursday, made two bogeys and a birdie in his first four holes Friday, then birdied the par-4 ninth and 10th to reach six-under for the tournament.
That pushed Johnson level atop the leaderboard after 11 holes with Marc Leishman, who opened with three pars to stand on six-under.
Leishman, trying to become the first Australian to win the Masters, opened with a 66 to share the first-round lead with Spain's Sergio Garcia.
Johnson seeks his first major title. He shared second behind Darren Clarke in the 2011 British Open and was in the hunt at the 2010 PGA Championship before a two-stroke penalty for grounding his club in a bunker ended his hopes.
Rickie Fowler, set to tee off in the final group of the day, was third on four-under after opening with a 68.
A group at three-under included Garcia, England's David Lynn and Justin Rose, South African Charl Schwartzel and Americans Fred Couples, Matt Kuchar and Jim Furyk.
Woods, who opened with a 70, was in a share of 11th as he awaited his tee time in the penultimate group.