(CNN) -- Tiger Woods took the halfway lead in the Tour Championship after a second round two-under par 68 at East Lake..
Woods splashes out of a bunker on the way to his two-under 68 at East Lake.
The world number one is bidding for his seventh victory in the PGA Tour this season and is one shot clear of his nearest challengers on five-under 135.
A closing bogey gave his chasers a glimmer of hope with Ireland's Padraig Harrington (69) and American Sean O'Hair (70) on 136.
South African Ernie Els was a further shot back on 137 after a 66 with five birdies in his last 10 holes.
Woods missed a birdie and eagle putts on the back nine and admitted he could have a more comfortable margin.
"Today's round probably could have been one or two better for sure," Woods told reporters.
"But, you know, overall I'm very pleased with my scoring the first two days."
Woods made three straight birdies from the seventh to take charge and overhauled first rounder leader O'Hair.
He is now well-placed to capture the PGA Tour's FedEx Cup series title and the $10 million bonus on offer as his closest rivals for that crown are not in halfway contention at East Lake.
In-form Harrington, who will play in the third round with Woods, would have to win the championship and hope Woods falls out of the leading places, while O'Hair needs a similar scenario and is focused on victory.
"A win is a win," he said. "Let's face it, I've got to win this golf tournament to win the $10 million. If I do my job, that's all I can do."
"I'm in good position as regards to the tournament, probably not the best position as regards to the FedEx Cup," Harrington said.
"It's a little bit out of my control. But I'm looking forward to the weekend. I left a few shots out there toward the end, but overall, I knew there was another 36 holes to play."