Thomas went only 13 holes for the second straight match in a 6-and-5 victory over Si Woo Kim. He advanced to the quarterfinals Saturday afternoon and moved one step closer to a chance to become No. 1 in the world.
Thomas, the No. 2 seed, and seventh-seeded Sergio Garcia were the only top-10 seeds to advance out of group play. Garcia lost in the fourth round to Kyle Stanley.
Ian Poulter won his fourth-round match against Louis Oosthuizen, putting him close to reaching the top 50 in the world. That would earn him a spot in the Masters.
Patrick Reed, one day after knocking out Jordan Spieth, lost to Alex Noren.