Error-strewn Federer’s vulnerability on his favourite surface could perhaps be explained by a back injury that made the 34-year-old miss last month’s French Open, but this was not the build-up to Wimbledon that the Swiss ace wanted.

The 19-year-old Zverev triumphed 7-6 (7/4), 5-7, 6-3 to reach only his second ATP Tour final after being beaten by Dominic Thiem on clay in Nice last month.

The tournament will see an all-German final after 192-ranked Florian Mayer crushed world No7 Thiem, 6-3, 6-4 in the second semi-final.

As Zverev bids for his maidencareer title, Mayer plays his sixth final and first in nearly five years as he targets a second ATP title after Bucharest in September 2011.

“It’s unbelievable to get a win against Roger, especially on grass,” said Zverev. “I played very good and served well once again. I think that helped me a little bit and I played well in the important moments.

“It’s nice to get a win like that. It’s nice with that kind of match going into Wimbledon and obviously into the final here as well. Don’t forget that that is a very big match for me. We’ll see what happens tomorrow but I’m happy with my performance today.”