Shelton will face Novak Djokovic on Friday for a berth in the final. Djokovic reached his record 47th Grand Slam semifinal, breaking a tie with Roger Federer for the most by a man, by defeating Taylor Fritz 6-1, 6-4, 6-4.
Asked whether he knew whom he'd play next, Shelton smiled and said, knowingly, "He's won maybe 23 of these? Something like that?" -- referring to Djokovic's total number of major championships. "It doesn't get much better than that."
Both the unseeded Shelton and the No. 10 seed Tiafoe, a 25-year-old from Maryland who was a semifinalist at Flushing Meadows a year ago, wore sleeveless muscle shirts. Shelton's was mostly black with fuchsia down the left side; Tiafoe's was green with a mix of colors on the front that Coco Gauff described as "confetti."