Kim Si-woo carded a three-under-par 69 on Saturday, while Jordan Spieth lost ground after a forgettable front nine.
Si Woo Kim will take a four-shot lead into the third round of the PGA Tour's Valero Texas Open after holding an ace at the 16th on Friday.
Thomas Pieters and Thomas Detry will hold a handsome five-stroke advantage for Belgium going into the final round of the World Cup of Golf.
Belgium and South Korea share the lead at the halfway mark of the World Cup of Golf after tough second-round conditions.
Malaysia's Gavin Green and Ben Leong teed off to a good start at the World Cup of Golf in Australia on Thursday.
Kim Si-woo's wayward putting proved costly as Satoshi Kodaira came out on top after three play-off holes at the RBC Heritage.
Rickie Fowler threatened, but Patton Kizzire held on to win the OHL Classic at Mayakoba by one shot.
Omnisport examines the leading challengers for U.S. Open glory ahead of the final round of the year's second major at Erin Hills.
Kim Si-woo was the most notable mover during the early stages of day two at Erin Hills, but things were going wrong for Paul Casey.
The youngest winner in The Players' storied history Kim Si-woo will be absent at the Byron Nelson this week as he recovers from an injury.