Scottie Scheffler insists his swing is "in a good spot" despite seeing his lead at the top of the Tour Championship standings cut to four shots on the second day. (More Sports News)
Scheffler, who is aiming to win his first FedEx Cup title, carded 65 in his opening round and entered the second round with a 10-shot lead.
However, the world number one saw American duo Collin Morikawa and Xander Schauffele close the gap during a weather-disrupted second round on Friday.
Scheffler carded a round of 66 to take himself to 21 under par, aided by two birdies in the final three holes to keep the chasing back at bay.
"I feel like my swing is in a good spot, and I've hit it nice the last couple of days," he said. "A lot of quality stuff out there, and in a good spot going into the weekend."
Morikawa is four shots off the pace after producing a superb eight-under 63, which was the best round of the day, and has surged up the standings to second place.
In an impressive round, he dropped just one shot on the 11th hole, but made amends on the back nine before closing with back-to-back birdies.
"He's going to continue to make birdies," Morikawa said about the possibility of catching Scheffler. "He's driving it really, really well here, and you're giving yourself enough wedges to make some scoring opportunities out there.
"For me, it's just about bringing energy and just staying alive out there."
Schauffele is in third, one shot behind compatriot Morikawa, after shooting an impressive second-round 64 to remain in the hunt for the $25million prize money.
There is then a four-shot gap until a group of three players, including Adam Scott, are tied for fourth place at 12 under, while Rory McIlroy is tied for 10th place on eight under.
