Rafa Nadal's preparations for Wimbledon were cut short when he was knocked out of the Halle Open by defending champion Philipp Kohlschreiber on Friday.
The German triumphed 6-3 6-4 just four days after Nadal won a record seventh French Open title at Roland Garros.
It was the first time Kohlschreiber had beaten the Spaniard after eight previous defeats, although this was their first meeting on grass.
The German will face the winner of Czech third seed Tomas Berdych's match against wildcard Tommy Haas in the semi-final, while number two seed Roger Federer plays Canada's Milos Raonic later on Friday.
(Writing by Toby Davis in London; editing by Pritha Sarkar)