The US swept Chile 3-0 in their Davis Cup group stage clash on Wednesday in China, despite looking the weaker side on paper. Unheralded American Reilly Opelka beat Cristian Garin in three sets ending in a tie-break before world number 40 Brandon Nakashima, a Davis Cup debutant, edged 22nd-ranked Alejandro Tabilo the same way. The US team wrapped up the doubles too after going right to the wire. “Hats off to our guys who were really digging deep, especially in the big moments,” US captain Bob Bryan said. “I don’t think it’s ever happened in Davis Cup that all matches went to the third set break…