Lee Westwood lost the Masters lead after a double-bogey on the final hole on day two at Augusta National.
The Englishman, 38, was leading going into the 18th, but dropped two shots to end on four under after a 73.
He said: "It was a disappointing way to finish. If you get out of position on this course it can punish you, but these things will happen to everybody.
"I thought I made a few putts that did not drop but I'm right in there for the weekend and that's where I want to be."
It looked as though Westwood would be topping the leaderboard for a second day after American Jason Dufner dropped a shot on the same hole, but instead Dufner took the clubhouse lead alongside his compatriot Fred Couples.
Long regarded as one of the best players in the game from tee to green, former world number one Westwood has yet to clinch one of golf's majors.
He has produced six top-three finishes in majors, including second place at Augusta National in 2010, and gave himself a flying start to this year's Masters with an opening five-under-par 67.
However, conditions were tricky on Friday as a chilly morning gave way to bright sunshine, quickening greens and shifting winds.
Westwood was unable to make early inroads as he parred the first nine holes. Though he bogeyed the tricky 11th, he did well to recover with birdies at the 12th and 15th before ending his round on a bitter note at the last.
"There was a lot more breeze today, and that obviously makes it play tougher," said the 21-time winner on the European Tour.
"The greens are drying out and getting a bit faster. And then the wind can play havoc with some of the second shots."