Jan-Lennard Struff rescued Germany in Sunday's final singles rubber to preserve their Davis Cup World Group status by sealing a narrow 3-2 play-off win against Poland.

Kamil Majchrzak's shock win over Florian Mayer earlier had put Poland back in the relegation play-off in Berlin by levelling at 2-2 after his team had lost both opening rubbers.

But Struff's 7-6 (7/4), 6-4, 6-1 win over Hubert Hurkacz in Sunday's final tie saw Germany narrowly avoid their first relegation from the Davis Cup's elite group for 13 years.

"We gave everything and at the end it finally worked. As a child, I always dreamed of being able to celebrate a situation like this. It was crazy," said Struff, 26, with a German flag in his hand.

Struff finished the job he started, having given Germany the lead with a victory over Poland's Kamil Majchrzak, 20, on Friday as the hosts finished the opening day 2-0 up after Florian Mayer also beat Hurkacz.

But Marcin Matkowski and Lukasz Kubot battled back superbly from losing the first two sets to claim a 6-7 (5/7), 4-6, 6-3, 6-4, 6-2 victory over Daniel Brands and Daniel Masur in Saturday's doubles, before Majchrzak beat Mayer to level the tie.

Struff, ranked 67th in the world, was Germany's hero of the hour, according to his Davis Cup captain Michael Kohlmann.

"He pulled it off well, was active and shifted the course of the game. Now he can be very, very proud of himself," said Kohlmann.

The last of Germany's two relegations from the Davis Cup's World Group was back in 2003.