Alexander Zverev defeated three-time major winner Stan Wawrinka in the Davis Cup on Friday as the German star returned to the courts for the first time since being cleared of domestic abuse.
The 25-year-old Zverev swept past Wawrinka 6-4, 6-1 in Trier to bring Germany level with Switzerland after the opening day of their qualifier.
On Tuesday, Zverev was told by the ATP that there was "insufficient evidence" to substantiate allegations against him of abusing a former girlfriend.
Former world number two Zverev always denied the claims, describing them as "baseless".
On Friday, Wawrinka, who helped his country win the 2014 Davis Cup, was returning to the team competition for the first time in eight years.
Now ranked 135 in the world, he was comfortably beaten for the fifth time in five meetings by Zverev.
"I think it´s important to go into tomorrow´s ties with a 1-1 scoreline," said Zverev after recording just a second match win in eight months.
He missed the last six months of the 2022 season having suffered ankle ligament damage in June during a French Open semi-final defeat to Rafael Nadal.
"That was the best match since my injury. It´s going in a positive way and I hope to continue progressing."
Marc-Andrea Huesler had given Switzerland the lead with a 2-6, 6-2, 6-4 win over Oscar Otte.
The tie continues on Saturday with a doubles and two singles rubbers as the Swiss look to beat Germany for the first time having lost all nine meetings since their maiden clash in 1939.
Mackenzie McDonald and Tommy Paul gave the United States a 2-0 lead in their qualifier against Uzbekistan.
McDonald, who knocked Nadal out of the Australian Open last month, eased past Sergey Fomin 6-4, 6-1 in Tashkent before Tommy Paul, a semi-finalist at the season-opening Grand Slam in Melbourne, defeated Khumoyun Sultanov 6-1, 7-6 (8/6).
Despite his lowly ranking of 480, Sultanov opened up a 4-0 lead in the second set over top-20 player Paul before the American´s greater experience paid off.
"He picked up his level a ton," admitted Paul. "I felt like I wasn´t prepared for it."
Of Saturday´s rubbers, he added: "A sweep would be nice — bring out the broomsticks!"
France, the 10-time champions, were 1-1 against Hungary in Tatabanya.
World number 182 Zsombor Piros stunned 45th-ranked Benjamin Bonzi 7-6 (7/4), 6-3 before Ugo Humbert levelled the qualifier by seeing off Marton Fucsovics 6-3, 6-2.
"It was my first match in the Davis Cup and I was very excited," said 24-year-old Humbert, the world number 86.
In Stockholm, Sweden opened up a 2-0 lead over Bosnia thanks to straight-sets wins by brothers Mikael and Elias Ymer.
Norway, without world number four Casper Ruud, slipped 2-0 down at home to Serbia, playing without recently-crowned Australian Open champion Novak Djokovic.
Andreja Petrovic, selected instead of French and US Open runner-up Ruud, is ranked a lowly 1,205 in the world.
He was defeated 6-1, 6-3 by 34th-ranked Miomir Kecmanovic in just 46 minutes.
Colombia and Britain ended the opening day level at 1-1 in Cota in suburban Bogota.
Nicolas Mejia, ranked 253rd in the world, got the hosts off to a strong start with a 6-2, 2-6, 6-4 victory over Dan Evans.
Cameron Norrie pulled Britain level with a 6-2, 7-5 victory over Nicolas Barrientos.
There are 12 ties taking place this weekend with the winners securing places in the group stage in September alongside defending champions Canada, 2022 runners-up Australia and wild cards Italy and Spain.
The eight best teams then go through to the Davis Cup Finals knockout stage in Malaga in November.
The qualifying matches taking place between Friday and Sunday are the first since the International Tennis Federation severed its partnership with investors Kosmos less than five years after a 25-year deal was signed.