Australian Adam Scott has emerged as Brooks Koepka's biggest threat after shooting his way into the final group at the US PGA Championship in Missouri.
Scott fired a day three best 5-under-par 65 at Bellerive Country Club to jump to outright second at 10 under, just two shots back of 54-hole leader Koepka (66).
Seeking to add a second major title to his 2013 Masters triumph, Scott will tee off in the last group at the year's final major alongside two-time US Open winner Koepka.
One shot back of Scott sharing third are superstars Jon Rahm (66) and Rickie Fowler (69), as well as overnight leader Gary Woodland (71).
The big-hitting Koepka threatened to run away with the lead on moving day, having led by five shots at one stage, but two bogeys in the middle of his back nine gave the rest of the field hope.
Scott putt on a ball-striking masterclass, hitting 10 of 14 fairways and 15 greens in regulation to be ranked number one on Saturday (local time) for approach play.
PGA Championship Leaderboard
-12 B Koepka
-10 A Scott
-9 R Fowler
-9 G Woodland
-9 J Rahm
-8 S Lowry
-8 J Day
-8 J Thomas
-8 T Woods
-8 S Cink
-8 C Schwartzel
The 38-year-old was also hot with the putter, rolling in six birdies to keep Koepka within striking distance.
Scott's countryman Jason Day struggled to hit top gear during a 67 which left the 2015 US PGA Champion at 8-under the card — but still in the hunt for a second major victory.
Day, who finished second at the 2016 PGA Championship and tied ninth at last year's edition, is joined in a share of sixth by several others including defending champion Justin Thomas and Tiger Woods (66).
The four-time PGA Championship winner Woods ignited hopes among enormous galleries at the St. Louis course when he picked up four shots on his front nine.
But an even-par back nine leaves Woods having to chase down a four-shot deficit if he is to earn his 15th major title.
Rounding out the Australian contingent is Marc Leishman (72) and Cameron Smith (73), who both tumbled down the leader board to be one over and three over respectively.
Meanwhile, Englishman Matt Wallace (2-under) hit a hole-in-one on the 16th, calling it, "the best shot of my life".