The Czech Republic beat the United States to reach the Davis Cup Final 8 after US Open finalist Ben Shelton and Learner Tien both lost their singles matches Saturday.
Jakub Mensik beat Shelton 5-7, 6-4, 6-3 to level the best-of-five series at 2-2 before Jiri Lehecka sent a roaring Prague crowd into raptures by beating Tien 6-3, 7-5 in the deciding singles.
It was a second straight loss for Shelton, a day after he was beaten by Lehecka.
American pair Christian Harrison and Austin Krajicek had made it 2-1 after winning their doubles match over Adam Pavlasek and Patrik Rikl 5-7, 6-3, 7-6 (8).
Austria made the Final 8 after Jurij Rodionov beat Belgium's Zizou Bergs 7-6, 6-3 to build an insurmountable 3-1 advantage. Austria also won the doubles match on the outdoor clay in Vienna, a day after it split the opening single matches with Belgium.
Toby Samuel and Wimbledon semifinalist Arthur Fery won their singles matches to put Britain up 2-0 at home to Ecuador.
It was Zverev's first match since winning the US Open final last weekend against Shelton. That came after the 29-year-old Zverev won his first Grand Slam title at the French Open in June.
The second-ranked Zverev, who had 15 aces, dominated on the indoor hardcourt in Halle, Germany, with Dodig having no break-point chances.
Doubles and reverse singles are scheduled for Sunday in the best-of-five match series. The winning team advances to the Final 8 in Bologna, Italy, in November.
South Korea earlier became the first Asian nation to reach the Final 8 after clinching its match against India 3-1.
The South Koreans came from a set down in both singles matches Friday to lead 2-0.
It lost the opening doubles Saturday but SoonWoo Kwon beat Sumit Nagal 6-1, 6-2 in the first reverse singles.
The Final 8 format was introduced in 2022.