Zverev assisted the reigning champions with wins in both singles and mixed doubles.
World number two Alexander Zverev and Laura Siegemund helped Germany defend their United Cup title, defeating Brazil in the mixed-team tournament.
Zverev secured the triumph by defeating Thiago Monteiro 6-4, 6-4, after Siegemund won 6-3, 1-6, 6-4 over Beatriz Haddad Maia, who is rated 63 places higher at 17.
After losing to China earlier, the South Americans were eliminated from group play in Perth. Germany faces China on Monday, with the victor progressing to the quarterfinals.
In Sydney, women’s world number four Jasmine Paolini defeated Belinda Bencic 6-1, 6-1 in just 57 minutes, helping Italy defeat Switzerland.
Men’s world number six Casper Ruud, meanwhile, withstood a stern test from Tomas Machac, but his efforts were in vain as Norway crashed into the Czech Republic.
Zverev broke Monteiro in the first game of each set, stopping him from threatening throughout the 80-minute match.
The one-two singles punch put Germany in an unexpected position at the tournament, which it won last year.
“This is the first time we’ve ever been up 2-0,” Zverev added. “Last year, I always played deciding mixed doubles matches.
“It’s wonderful to have this (tie) in my luggage. I’m delighted to be playing for Germany again.”
Siegemund struggled for over two and a half hours to defeat Haddad Maia, winning five consecutive first-set games before losing the second set.
After three consecutive service breaks late in the final set, the German took a 5-4 lead and won on her first match point.
“It’s good to pull your best game out of the pocket in the first match of the season,” she told the crowd. “I tried to stay cool and take my advantages.”
Paolini had a spectacular 2024, coming second at Roland Garros and Wimbledon, and she carried that momentum into her first match of the new season.
Bencic, a former world number four, is on her comeback after having a baby and was absolutely overpowered.
“I had a really excellent match. “Everything went really well today,” Paolini remarked.
“I was serving and returning well, and I think that was the key.”
Her teammate Flavio Cobolli had earlier upset Dominic Stricker 6-3, 7-6 (6/2) to give Italy a 1-0 advantage.
Ruud, the highest-ranked Norwegian in history, was pushed through his paces for almost three hours before defeating Machac 7-6 (7/6), 5-7, 6-4.
