Brooks Koepka has improved his chances of taking over as the No. 1 golfer in the world, shooting a 5-under 67 Saturday to take a four-stroke lead after three rounds of the CJ Cup at Nine Bridges.

Koepka had a three-round total of 13-under 203. Ian Poulter, who shot 68 Saturday, was tied for second place with second-round leader Scott Piercy, who had a 72.

The 28-year-old Koepka, who trailed by one stroke after two rounds, will move to the top of the world rankings if he wins the tournament and former No. 1 Justin Thomas, the defending champion here, does not finish any better than second.

Justin Thomas of the United States watches his shot on the 10th hole during the first round of the CJ Cup PGA golf tournament at Nine Bridges on Jeju Island, South Korea, Thursday, Oct. 18, 2018. (Park Ji-hoYonhap via AP)

Justin Thomas of the United States watches his shot on the 10th hole during the first round of the CJ Cup PGA golf tournament at Nine Bridges on Jeju Island, South Korea, Thursday, Oct. 18, 2018. (Park Ji-hoYonhap via AP)

Thomas shot a 71 Saturday and is at 1-under, 11 strokes behind Koepka and tied for 43rd.

Dustin Johnson is currently No. 1, Koepka is second and Thomas third.

There were six golfers tied for fourth, including Rafa Cabrera Bello, who shot 65 Saturday, and first-round leader Chez Reavie (70).

Justin Thomas of the United States blasts a shot on the 10th hole during the first round of the CJ Cup PGA golf tournament at Nine Bridges on Jeju Island, South Korea, Thursday, Oct. 18, 2018. (Park Ji-hoYonhap via AP)

Justin Thomas of the United States blasts a shot on the 10th hole during the first round of the CJ Cup PGA golf tournament at Nine Bridges on Jeju Island, South Korea, Thursday, Oct. 18, 2018. (Park Ji-hoYonhap via AP)

Shubhankar Sharma of India had the round of the day, a 64, to move to 3-under, 10 strokes behind Koepka.

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