Dustin Johnson accepted he will need "some help" from runaway leader Brooks Koepka to have any chance of winning the PGA Championship.
Koepka will carry a record seven-stroke lead into the final round at Bethpage Black in New York as he bids to retain his title.
Johnson is in a four-way tie for second at 5 under after carding a 1-under 69 in the third round.
The world No. 1 knows Koepka — who shot a 70 to get to 12 under and grab the biggest 54-hole lead in tournament history — is in control.
"I'm going to need some help from him," Johnson said.
"Then, I'm going to have to play very, very well."
Johnson was left to rue a poor back nine, where he mixed four bogeys with two birdies after reaching 7 under at one stage.
Highlights from @DJohnsonPGA's third round.#PGAChamp pic.twitter.com/9cQjIQH2iw
— PGA Championship (@PGAChampionship) May 19, 2019
The 2016 U.S. Open champion was satisfied with his form, but lamented some missed chances.
"I felt like I played well, just made too many bogeys. It wasn't one thing or the other. Wind got me a couple times," Johnson said.
"Hit some drives that I thought should have ended up better than they did.
"Seemed like every time I got just a little bit out of position, I made bogey. Missed quite a few short birdie putts. Missed a couple short par putts.
"Overall, I felt like I swung the golf club very well. I drove it well. I putted well. I missed a few short ones."