Federer, Nishikori reach Halle semis

Halle, Germany ( - Six-time Halle champion Roger Federer and fourth-seeded Kei Nishikori secured berths in the semifinals at the grass- court Gerry Weber Open, a Wimbledon tune-up.

The second-seeded former world No. 1 great Federer was scheduled to meet Yen-Hsun Lu in Friday's quarterfinals, but the Taiwanese slugger pulled out of the draw, citing a back problem, while the Japanese Nishikori took care of American Steve Johnson 6-1, 7-6 (7-4) at Gerry Weber Stadium.

Federer and Nishikori will do battle on Saturday.

The seven-time Wimbledon champion Federer beat Russian Mikhail Youzhny in last year's Gerry Weber finale. The 32-year-old icon owns more grass-court titles (13) than any other player since the Open Era began in 1968.

The other semifinal will pit Germany's own Philipp Kohlschreiber against Colombian fellow non-seed Alejandro Falla. The 2011 Halle champion and 2008 runner-up Kohlschreiber outlasted wild card and fellow German Dustin Brown 6-4, 5-7, 7-6 (18-16) in 2 hours, 10 minutes, while Falla beat German wild card Peter Gojowczyk 7-6 (7-4), 7-6 (7-2) on Day 5. The giant-killer Brown, who launched 19 aces in his loss against Kohlschreiber, stunned French Open champion Rafael Nadal here on Thursday.

The 2014 Halle champion will claim $175,000.