Germany, Serbia, Russia lead on Day 1 of revamped Davis Cup
The third-ranked Zverev, who has repeatedly criticized the event's format changes, eased past Peter Nagy 6-2, 6-2 to double Germany's advantage after Philipp Kohlschreiber rallied to beat Zsombor Piros 6-7 (6), 7-5, 6-4.
All 12 ties are being played over two days. The reverse singles are scheduled immediately after the doubles on Saturday. Also, all rubbers have been shortened to best-of-three.
Austria came from behind against Chile as Dennis Novak defeated Christian Garin 6-4, 6-4 in the second match, after Nicolas Jarry edged 19-year-old Davis Cup debutant Jurij Rodionov, who replaced Dominic Thiem.
Also, Taro Daniel edged Zhang Ze 7-6 (3), 6-4 to level for Japan against China, after Li Zhe gave the hosts a surprise lead by defeating Yoshihito Nishioka 6-3, 6-2.
The 12 winners of this weekend's qualifiers join six already qualified nations at the Davis Cup Finals in Madrid in November: Defending champion Croatia, 2018 runner-up France, semifinalists the United States and Spain, as well as wild cards Britain and Argentina.
At the finals, the 18 nations will compete in six groups of three teams, with all group winners and the two best second-ranked teams advancing to the quarterfinals.