His next start saw him tied for 22nd at the Genesis Open, before finishing tied for 12th at the WGC-Mexico Championship. His next event was also a World Golf Championship event; the WGC-Dell Technologies Match Play. Spieth was seeded 5th, but failed to progress out of the pool stage; a surprise loss to Japan's 54th seed Hideto Tanihara (who would go on to reach the semi-finals) in his opening match, ultimately costing him.