Scotland's Russell Knox vowed to take an aggressive approach as he tries to overhaul Japan's Hideki Matsuyama and make a successful title defence in the HSBC Champions.
Knox trails the in-form Matsuyama by three shots heading into the final round in Shanghai as he tries to b ecome only the second player after Tiger Woods to retain a World Golf Championships title.
Matsuyama, who is a career-high 10th in the world after winning the Japan Open a fortnight ago and finishing second in Malaysia last week, carded a bogey-free 68 to finish 17 under par, with Knox carding five birdies and one bogey in his 68.
American Daniel Berger is a shot behind Knox after a third round of 67, with Italy's Francesco Molinari and American Bill Haas another stroke adrift on 12 under.
"I'm not going to give up my title without a big fight," Knox said. "I look forward to every minute tomorrow and see what happens.
"The way Hideki played today, he's probably going to play similar tomorrow. I'm going to have to be foot down, be aggressive and try and catch him. I'm thrilled to be in this position.
"I'll probably have to play close to the round of my life. I'm going to have to play excellent golf, be patient and hole some putts. It's going to be difficult but I can't wait for it."
Knox, who was inches away from a hole-in-one on the fourth, was two behind Matsuyama when he picked up another shot on the 13th, only to find water with his approach to the par-five 14th as Matsuyama hit the green in two.
A two or three-shot swing looked certain and Matsuyama duly two-putted from long range for birdie, but Knox holed from 25 feet for an unlikely par and birdied the next for good measure.
"After hitting it in the water on 14, to make a massive putt for par was huge," the 31-year-old from Inverness added. "And then of course I birdied the next, which was a massive momentum change. Those little moments are what add up in a tournament."
Knox was unable to find any more birdies on the closing stretch and Matsuyama two-putted the 18th for a closing birdie to extend his lead as he looks to become the first Japanese player to win a WGC event.
"The first two days, making lots of birdies, it's a lot of fun," the 24-year-old said. "But today, when you're in a position to win, playing smart and making no bogeys was very satisfying to me.
"Everyone is so good. I know I'm going to have to make some birdies. But I think the key for tomorrow's round will be not making any bogeys."
Rory McIlroy was within four of the lead when he produced a brilliant recovery shot on the par-five eighth to set up his third birdie of the day, but the world number three bogeyed the 11th, 12th and 15th to slip down the leaderboard.
Birdies on the 16th and 18th repaired some of the damage and gave McIlroy a round of 70, but that left the 27-year-old eight shots off the lead.
Thomas Pieters, Shane Lowry, Xinjun Zhang, Henrik Stenson and Matt Kuchar were alongside McIlroy on nine under, with Kuchar's 68 including a hole-in-one on the 17th.
A car had been on offer for an ace if the hole measured more than 200 yards, but the tee had been moved forward to make it 193.
"My caddie alerted me so I literally found out a minute before my shot," Kuchar said. "I guess the way to describe it is the saddest hole-in-one ever, in that I knew I just made a hole-in-one and I was teased by this beautiful car sitting there that is not to be mine.
"We all had a good laugh about it so it wasn't too bad. Henrik came up and said, 'It's my fault, the back tee box was not in very good shape'.
"He was the one that asked for the tees to be moved forward and I guess that made the hole far too easy. So yeah, he owes me something."