(Reuters) - Second seed Ivo Karlovic of Croatia served 23 aces as he overpowered Germany's Dustin Brown 7-6(3) 6-3 in the quarter-finals of the Hall of Fame Tennis Championship in Newport, Rhode Island on Friday.
Karlovic, who broke Brown in the first game of the second set before sealing victory in just over an hour, will face fourth-seeded American Jack Sock in Saturday's semi-finals.
Sock advanced when Czech Jan Hernych retired from their quarter-final after he sustained a knee injury during the second game of the match.
"When a guy hits 23 aces and doesn't let you see any second serves, it's going to be impossible to break him," Brown, an unorthodox player known for his touch and outrageous drop shots, told reporters after losing to the 24th-ranked Karlovic.