Tiger Woods scrambled for an even- par 71, while Lee Westwood took advantage of softer conditions early Friday to post a 3-under 68 at the British Open Championship.
The duo share the clubhouse lead at 2-under-par 140. They were joined there by Henrik Stenson, who posted his second straight 70.
Woods had a pair of early birdies, but struggled through the middle of his round. After six consecutive pars, the three-time Open champion rolled in a birdie putt at the last to grab a piece of the lead.
Westwood, the 2010 runner-up, birdied six of the first 10 holes to gain a share of the lead at 5-under par. However, he stumbled to three bogeys in the last six holes to walk off the course three behind overnight-leader Zach Johnson, who had yet to tee off.
With the wind blowing a different direction than it had in the first round, Westwood posted the fourth round in the 60s, and ninth under-par round, in the first 51 players to finish their second rounds.
Martin Laird is the only other player in red figures that is through 36 holes. The Scotsman managed an even-par 71 to finish two rounds at 1-under-par 141. American Ryan Moore posted a 70 to end 36 holes at even-par 142.
Woods had two birdies and two bogeys on his opening nine. After dropping a shot on the 11th to slip to minus-1, Woods parred his next six holes. At the last, he rolled in a 12-footer for birdie to end at 2-under par.
"It was hard. The wind obviously was a totally different direction, and it was starting to freshen up. (Graeme McDowell) and I were talking out there about the greens being totally different speeds," Woods said in a television interview. "The run-ups were softer and then they started drying out towards the end. All the up-hill putts, we never got one to the hole, but then the downhill putts were running out."
Westwood flew out of the gate with birdies on the first two holes. He moved to 2-under with his second birdie in two days at the fifth.
The Englishman also birdied eight and nine to get within one of Johnson's lead. Westwood kicked in a 3-footer for birdie at 12 to join Johnson at minus-5.
However, Westwood faltered to bogeys at 13 and 14 to slip two back. He finished with another bogey at the last to end at minus-2.
"I felt really good. It's playing tough out there. The wind is a different direction that the practice rounds ... so you've probably got to make your score going out, then hold on coming in," Westwood said on TV.
Stenson opened with a birdie at the first, then posted four straight pars. He faltered to a double-bogey on the sixth, but came back with birdies at seven and nine to make the turn at 2-under par.
The Swede, who shared third place in 2008 and 2010, traded a bogey for a birdie from the 10th. Stenson tripped to another bogey at the 15th, but birdied the 17th for the second day in a row to end at minus-2.
Former Open champion Darren Clarke (71) was joined at 1-over-par 143 by five other players. Former major winners Charl Schwartzel (68), Masters champ Adam Scott (72) and Webb Simpson (70) also stand at plus-1, as does John Deere winner Jordan Spieth (74).
Mark O'Meara (78) and Tom Lehman (77), both former Open champions, fell to 3- over-par 145. McDowell managed a 71 to end two rounds at plus-4.
The cut line currently stands at 5-over-par 147. Among those outside the number with the main part of the late wave early on their front nine are Padraig Harrington, Paul Lawrie, Bill Haas, Jim Furyk, Luke Donald and Rickie Fowler.