Jason Day hopes to stretch lead at Bridgestone Invitational

Jason Day's plan for the Bridgestone Invitational was to get in the lead as quickly as possible and expand it from there in Akron, Ohio.

He took care of the first part Friday by relying on his sharp short game and a pair of late birdies for a 1-under 69 that gave him a one-shot lead over David Lingmerth going into the weekend.

Day, the world's No. 1 player, had a 20-foot birdie putt from the fringe on the final hole, and when his putter bumped up against the collar on the way back, he rapped it too hard and then missed the 6-foot par putt.

"I was very cross with myself when I was walking off," Day said. "The great thing is that once I do silly things like that on 18, I soon forget about it, and I just need to start focusing on tomorrow's round.

"But I know that I'm putting good because I'm holing putts. And if I can give myself the opportunities, I'm hoping that I can stretch that lead over 54 holes, and then hopefully by 72 holes, I can stretch that lead even more."

Day was at 4-under 136, matching Tiger Woods in 2005 for the highest 36-hole score to lead this World Golf Championship.

Windy conditions

Meanwhile, Lingmerth shot a 67 that tied for the lowest score of the second round, where scoring was hampered by wind.

William McGirt, who began the second round with a three-shot lead, stayed in front until he went over the par-5 16th with a wedge and made bogey, and then chopped up the 18th hole on his way to a double bogey for a 74.

McGirt had a 74 and was two shots back at 138, along with Emiliano Grillo and Scott Piercy.

"Trying to figure out the wind was impossible," McGirt said. "It was a lot of down off the left with a touch of in off the right. I mean, who knows?"

Only nine players remained under par.

Rare eagle on 16

Justin Thomas hit a tee shot that caught the slope perfectly on the par-5 16th and didn't stop rolling until it was 414 yards away. 

"I can't hit another drive that hard," Thomas said.

He hit 5-iron just left off the green in a nasty lie and figured he had squandered a good scoring chance until his chip hit the pin and dropped for an eagle, the first one on the 16th since 2008.

Thomas fired a 69 and joined Jordan Spieth, Adam Scott and Kevin Kisner at 1-under.

Spieth is trying to pick up the pace, aware of criticism that he is playing too slow. Having spoken with his coach, he thinks it gives him an edge to step up and hit it.

"The quicker part actually helps me because then I just get up there and fire away," he said.

His only issue was keeping it in play, though he wasn't alone in those struggles.

'Difficult for everyone'

U.S. Open champion Dustin Johnson hit only six fairways in his round of 73 that put him at 2-over, though he's still only six shots behind Day.

Day is trying to join Woods and Phil Mickelson as the only players to win at least two World Golf Championships in the same year. Day won the Dell Match Play in March in dominant fashion, while his victories this year at the Arnold Palmer Invitational and The Players Championship were a little closer.

It didn't feel like his best golf on Friday, though the conditions had something to do with that.

"I think over the next two days, it's going to be very difficult for everyone," Day said. "I would love to be able to give myself more opportunities, and if I can do that, hopefully I'm holding the trophy at the end of the week," he added.

"I've just got to try and get it done."