Hamburg: Roger Federer was stunned by World Number 114 Argentine qualifier Federico Delbonis as he lost in straight sets by 7-6 (7), 7-6 (4) in the semi-final of the German Tennis Championships here on Saturday.

It’s going to be a maiden final for the World No. 114, who managed to clinch this thrilling win against the 17-time Grand Slam champion and four-time winner in Hamburg. Federer took a wild card for the Hamburg tournament after he was stunned by Sergiy Stakhovsky in the second round at Wimbledon.

Delbonis will face Fabio Fognini in the final tussle of the tournament. Italian knocked out third-seeded Nicolas Almagro of Spain 6-4, 7-6 (1) to reach the finals.

Meanwhile, in the Swedish Open, Serena Williams breezed through the semi-finals as she outwitted Klara Zakopalova 6-0, 6-4. Williams showed her dominance as she managed to win the first eight games in a row but Czech did well to take the second set to 2-2.

In the other semi-final of the contest, Sweden's Johanna Larsson did a massive turnaround as she outplayed Italy's Flavia Pennetta 2-6, 6-3, 6-4.