Justin Rose pledged to put his foot down in pursuit of a second straight Turkish Airlines Open title and a return to the top of the world rankings after suffering a costly concentration lapse in Antalya.
Rose began the third round at the Regnum Carya Golf Resort with a two-shot lead, but ended it three behind China's Li Haotong after hitting three balls into the water in the space of nine holes in an uncharacteristically untidy 69.
Li's flawless 63, which included an eagle and six birdies in the first 12 holes, gave the 23-year-old a 17-under-par total of 196 and a three-shot lead over Rose and France's Alexander Levy, with 2016 winner Thorbjorn Olesen a stroke further back.
Paul Dunne is best of the Irish (join 12th) on nine under after a 69, with Shane Lowry a shot behind him following a 67 and Padraig Harrington seven under after carding an even-par 71.
Harrington bogeyed three of his front nine but bounced back with an eagle on 12 and birdie on 13.
"I struggled with my focus and concentration and made a couple of questionable decisions," admitted Rose, who will replace Brooks Koepka as world number one if he can make the successful title defence of his career.
"It was maybe a little bit of tiredness at the end of a long season so I have to make sure I come out on Sunday more focused.
"Three balls in the water and still shot 69 so there's some good stuff still happening. It was a bit of a disappointing finish but there is so much golf to be played and I am not really too fussed about the position I'm in.
"Being three shots back you have to put your foot down and go for it. It does not mean reckless aggression, but you have to pick your moments to be aggressive.
"In some ways there's nothing to lose and everything to gain. I'm going to have to shoot in the mid 60s and it's maybe easier than if I was one ahead."
Li chipped in for his fifth birdie of the day on the ninth to cover the front nine in 29 and took the outright lead in even more spectacular style by holing out from 173 yards for an eagle on the next.
A birdie on the 12th took him three shots clear and although Rose closed to within a shot after birdies on the 11th and 12th, dropped shots on the 13th and 18th left the Olympic champion facing an uphill battle.
Li has finished no worse than 11th in his last three starts and birdied four of the last six holes to edge out playing partner Rory McIlroy in the final round of the Dubai Desert Classic in January.
"Those three weeks gave me a lot of experience and confidence, especially against the best golfers in the world," Li said. "I definitely got a lot of confidence from Dubai and since then playing a lot of big events.
"It's going to be an exciting day tomorrow and I'm looking forward to go against Rosey, especially in a Rolex Series Event. I really want to win this week and play my best tomorrow."