A second-string United States team extended its Davis Cup winning streak by dismantling Germany to top Group C in Zhuhai, China, on Saturday after both countries had secured their spots in the quarterfinals.
The 32-time winners were without big names like US Open runner-up Taylor Fritz, Tommy Paul and Frances Tiafoe for the group stage this week but still had plenty of firepower to down Germany and complete a third straight win.
Brandon Nakashima gave the Americans an unassailable 2-0 lead by comfortably beating Maximilian Marterer 6-4, 6-2 in the second singles match of the day.
"It's been unbelievable this whole week. It's special to be part of this team," said Nakashima, who sealed his third victory in his debut campaign to stay perfect. "To represent the country has always been a dream of mine since I started playing tennis, so I'm super happy that I was able to get three wins on the board for the team."
World No. 309 Reilly Opelka, back on the circuit after hip and wrist surgeries, saved three match points and cranked up his serve when it mattered to beat Henri Squire 6-7 (4), 7-6 (9), 6-3 earlier in the day.
The top two countries from four groups based in different cities will go through to the knockout stage to be held in Malaga, Spain, in November.
Heavyweights Spain and Australia have also qualified along with the United States and Germany.
Belgium faces Brazil in Bologna, Italy, later hoping to go through from Group A. Finland, last year's surprise semifinalist, meets Argentina in Manchester, England, needing a win to stay alive in Group D.