Halle - Seven-time champion Roger Federer on Friday reached the Halle semi-finals where he will face Croatian giant Ivo Karlovic who fired a record-breaking 45 aces in his last eight clash.
World number two and top seed Federer defeated Germany's Florian Mayer 6-0, 7-6 (7/1) as he continues his build-up to an assault on an eighth Wimbledon title.
Federer required just 19 minutes to take the first set against Mayer before going on to conclude the tie in a little over an hour.
Karlovic battered his way into the semi-finals by smashing 45 aces past a bewildered Tomas Berdych en route to a 7-5, 6-7 (8/10), 6-3 victory.
The 36-year-old Karlovic, who stands 2.11m tall, won the match with the last of his aces and now has 94 on the Halle grass courts from three rounds of tennis.
His record came just two days after Germany's Sabine Lisicki blasted 27 aces in a match in Birmingham - a new record for the women's tour.
Japan's world number five Kei Nishikori also landed in the semi-finals after beating Poland's Jerzy Janowicz 6-4, 5-7, 6-3.