Top-seeded Roger Federer was taken to the limit on Friday before coming through for a 7-6 (4), 3-6, 7-5 victory over Florian Mayer and a place in the semifinals of the German Tennis Championships.
Federer is playing his first tournament since losing in the second round of Wimbledon.
A four-time champion on the clay courts of Hamburg, Federer needed two hours to overcome Mayer. Federer was down 5-1 in the second set, won the next two games but then faltered again. He double-faulted and then produced two straight forehand errors to give up the set.
In the third, Federer broke serve twice, only to see the German re-break both times. But with the match on the line, the Swiss former No. 1 raised his game considerably. He broke serve with the loss of a point for a 6-5 lead and served out the match at love, hitting a service winner on match point.
He next plays Argentine qualifier Federico Delbonis, who upset 14th-seeded Fernando Verdasco of Spain 6-7 (5), 7-6 (8), 6-4 to make the semifinals of a tournament for the second time in his career.
Fabio Fognini of Italy beat Tommy Haas for the second time in two weeks to also advance to the semifinals.
Fognini prevailed 6-2, 6-4 over the second-seeded home favourite. The 12th-seeded Italian is looking for his second straight title after winning his first tournament in Stuttgart, where he beat Haas in the quarterfinals.
Fognini next faces third-seeded Nicolas Almagro of Spain, who came from behind to beat defending champion Juan Monaco of Argentina 4-6, 6-0, 6-3.
The fifth-seeded Monaco beat Almagro in the Hamburg semifinals last year. Almagro was runner-up in Hamburg two years ago, while Monaco beat Haas for the title last year.
Delbonis' previous semifinal appearance was two years ago, also on clay and also in Germany, in Stuttgart.
After fending off a pair of match points in the second set, Delbonis failed to serve out the match at 5-3. He then wasted two match points on Verdasco's serve before the Spaniard double-faulted on the third.