Croatia's Ivo Karlovic broke the record for most aces served in a three-set ATP Tour match in his victory over Czech Tomas Berdych at the Gerry Weber Open.
The world number 27, who is 6ft 10ins, fired 45 aces in a 7-5 6-7 (8-10) 6-3 win over the third seed in Halle.
He will play seven-time champion Roger Federer in the semi-finals after the Swiss beat Florian Mayer 6-0 7-6 (7-1).
French fourth seed Gael Monfils retired injured from his quarter-final and is now a doubt for Wimbledon.
Monfils crashed into a side wall when trailing 6-1 1-0 to Italy's Andreas Seppi and has been diagnosed with an adductor strain.
Seppi will face Japanese second seed Kei Nishikori, who overcame Poland's Jerzy Janowicz 6-4 5-7 6-3.
The 36-year-old Karlovic, who shared the previous record of 44 aces with Australian Mark Philippoussis, said: "I always like when I'm best at something, so if it's aces I'm happy about it," he said.