Roger Federer stepped up his grass game as the start of Wimbledon looms, holding off Australian Matthew Ebden 7-6 (7/2), 7-5 in their quarter-final at the ATP Halle tournament on Friday. With his world number one ranking on the line, the Swiss is sparing no effort to make sure he lifts a tenth title at the event on Sunday. He will next play US qualifier Denis Kudla who beat Yuichi Sugita 6-2, 7-5.

The victory was the 19th in a row on grass for the 36-year-old Federer, who last lost on his favourite surface in an opening match in Stuttgart a year ago, although the 20-time Grand Slam champion atoned last weekend, winning that tournament for the first time. The other semi-final will pit Roberto Bautista Agut against Borna Coric. Fourth seed Bautista Agut defeated Russian Karen Khachanov 6-3, 6-7 (3/7), 6-3 while Croatian Coric eliminated Italy's Andreas Seppi 7-5, 6-3. Failure by Federer to win the grasscourt title would send rival Rafael Nadal back to the top spot going into Wimbledon which starts on July 2. "I felt I had to push myself today," Federer said. "It didn't come as easy as it did in other matches.