Stan Wawrinka took Switzerland to the Davis Cup Finals group stage on Saturday, winning a rollercoaster deciding clash against Germany, just weeks shy of his 38th birthday.
Three-time Grand Slam title winner Wawrinka, who helped the Swiss to the Davis Cup title alongside Roger Federer in 2014, defeated Daniel Altmaier 6-3, 5-7, 6-4 as his country triumphed 3-2 in their qualifying tie.
Former world number three Wawrinka, now down at 135 after a long spell rebuilding his career following two foot surgeries, was playing in the tournament for the first time in eight years having made his debut in 2004.
By contrast Altmaier, 13 years younger, was making his Davis Cup debut in Trier.
Wawrinka, who turns 38 next month, had lost his singles opener on Friday in straight sets to Alexander Zverev.
He was on the losing side again earlier Saturday when he and Dominic Stricker were beaten in the doubles 6-7 (3/7), 6-3, 6-4 by Tim Puetz and Andreas Mies.
However, Marc-Andrea Huesler then stunned world number 14 Zverev 6-2, 7-6 (7/3) to bring Switzerland level at 2-2, setting the stage for Wawrinka's moment in the spotlight.
"I'm happy that I won one point and the last one was the most important," said Wawrinka.
"We have a great team. They've been building this team for the last few years. I was happy to come back if they needed me."
The United States, who have won the 123-year-old tournament on a record 32 occasions, also booked their place in September's group stage by seeing off Uzbekistan in Tashkent.
Experienced doubles pair Austin Krajicek and Rajeev Ram cantered to a 6-2, 6-4 win over Sanjar Fayziev and Sergey Fomini in just 52 minutes.
"I was so excited to see Raj and Austin play today," said US captain David Nainkin whose team were 2-0 up overnight.
- 'Freight trains' -
"They came out really sharp and got the early break in the first set. After that it was like two freight trains, there was no stopping them."
Serbia shrugged off the absence of Novak Djokovic to comfortably defeat a Norway team missing world number four Casper Ruud.
Ahead 2-0 after Friday's opening singles in Oslo, Nikola Cacic and Filip Krajinovic saw off Viktor Durasovic and Herman Hoeyeraal 6-4, 3-6, 6-4 for the key point.
France, the 10-time champions, made the next round with a win over Hungary.
Ugo Humbert, making his tournament debut this weekend, sealed the tie with a 6-3, 6-3 victory over Fabian Marozsan in Tatabanya in the deciding singles.
France were given a scare when Hungary surprisingly claimed the doubles rubber as Marozsan and Mate Valkusz defeated Nicolas Mahut and Arthur Rinderknech 6-2, 7-6 (7/4) before Adrian Mannarino levelled at 2-2 with a straight sets win over Marton Fucsovics.
"I am so proud of this team," said Humbert.
Sweden also made it through to the September group stage with a 3-1 win over Bosnia.
The Swedes led 2-0 overnight in Stockholm before Bosnia cut the deficit when Mirza Basic and Tomislav Brkic downed Andre Goransson and Elias Ymer in straight sets.
World number 60 Mikael Ymer sealed the tie with a 6-1, 1-6, 6-3 win over Damir Dzumhur.
Britain defeated Colombia 3-1 when Cameron Norrie edged Nicolas Mejia 6-4, 6-4 for his second singles win of the weekend.
Croatia, the champions in 2005 and 2018, are 2-0 up on Austria in Rijeka after the first day with Borna Coric seeing off Dennis Novak 6-3, 7-5 and Borna Gojo getting the better of Dominic Thiem 6-3, 7-6 (7/2).
Chile are 1-1 at home to Kazakhstan, Belgium lead South Korea 2-0, the Netherlands have a 2-0 advantage over Slovakia, Finland and Argentina are 1-1 while the Czech Republic are 2-0 up on Portugal.
There are 12 ties 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 finals stage in Malaga in November.