Reilly Opelka and Brandon Nakashima won their respective singles matches before Austin Krajicek and Rajeev Ram teamed up to polish off the United States' 3-0 win over Chile on the second day of the Davis Cup Finals group stage Wednesday in Zhuhai, China.

Opelka, No. 309 in the ATP rankings, bombarded Cristian Garin with 27 aces and overcame 40 unforced errors to upset the 115th-ranked Chilean 6-3, 4-6, 7-6 (3), to open Group C play.

Nakashima secured the Americans' victory by downing Alejandro Tabilo 7-6 (5), 2-6, 7-6 (3), despite converting none of his seven break point opportunities and notching just 39 winners compared to Tabilo's 55. Nakashima won 21 of his 39 second serve points (53.8 percent).

Krajicek and Ram saved four of five break points to outduel Tomas Barrios Vera and Matias Soto 4-6, 6-4, 7-6 (3).

Spain matched the United States' success with a 3-0 sweep over the Czech Republic in Group B action in Valencia, Spain.

World No. 3 Carlos Alcaraz was locked in a battle with Tomas Machac before the latter retired in the opening game of the third set with leg cramps. Alcaraz had lost the opening set 6-7 (3) before recovering to win the second 6-1.

The 21-year-old secured the sweep alongside Marcel Granollers in a 6-7 (2), 6-3, 7-6 (2) doubles win over Jakub Mensik and Adam Pavlasek.

Roberto Bautista Agut handled Jiri Lehecka in straight sets, 7-6 (1), 6-4, for Spain's first win.

Group A play in Bologna, Italy, saw the host nation defeat Brazil, 2-1. Matteo Berrettini dispatched Joao Fonseca 6-1, 7-6 (5), before Matteo Arnaldi outlasted Thiago Monteiro 7-5, 6-7 (4), 7-6 (5).

Brazil salvaged the doubles match, with Rafael Matos and Marcelo Melo defeating Simone Bolelli and Andrea Vavassori 6-7 (3), 7-6 (6), 7-5.

Great Britain used the same formula to beat Finland, 2-1, in Group D action in Manchester, England. Daniel Evans and Billy Harris won their respective singles matches before Evans and Neal Skupski dropped the doubles draw to Harri Heliovaara and Otto Virtanen, 7-6 (4), 7-5.

Evans beat Eero Vasa 7-6 (3), 6-2, while Harris downed Virtanen 6-4, 7-6 (4), in singles play.

The five-day group stage continues Thursday. The Netherlands faces Brazil in Group A action, while Australia and the Czech Republic meet for a Group B battle. Group C play features Germany against Chile, and Group D pits Canada against Finland.

The United States faces Slovakia on Friday before closing out its group play slate against Germany on Saturday.

--Field Level Media