Former world number one Roger Federer admits he needs to rest ahead of Wimbledon, after he suffered a shock defeat to teenager Alexander Zverev in the Gerry Weber Open.

Federer, priced at 11.00 to win at Wimbledon, had been aiming for a ninth Halle singles title and his fourth in a row but he was stunned by the German who eventually won 7-6 (7-4) 5-7 6-3 to advance to the final.

The 19-year-old became the first teenager to beat Federer since 2006 and the result comes as a huge blow to the Swiss ace ahead of the next Grand Slam. He never managed to take control and Zverev was too strong with his own serve throughout the entire match.

The 34-year-old is hoping to win his eighth singles Wimbledon title but Saturday’s loss was his second on grass in the last four weeks.

He lost to Dominic Thiem in the semi-finals of the Mercedes Cup in Stuttgart last week and the Swiss star now admits he must rest up before trying to win another Grand Slam at SW19.

“There are little things that have to fall into place then I will play better and feel better,”

he said. “I hope that happens sooner rather than later. “I have to see how I feel at the beginning of Wimbledon. I know the dangers of the early rounds of any Grand Slam.

“I now know what I need to work on in the next 10 days. Clearly I need some rest.

It has been intense and busy and that is exactly what I have needed, and at least I have a clear picture if where my game is at and what I need to do.”