World number one Roger Federer advanced to the quarter-finals of the Halle Open on Thursday with a 7-5, 6-3 victory over Jan Vacek of the Czech Republic.
Federer, four times winner of the grass tournament in Halle that serves as a tune-up for Wimbledon, extended his winning streak on grass to 56.
The five-times Wimbledon champion, who was crushed by Rafael Nadal in the French Open final on Sunday, had skipped the German tournament 12 months ago.
