Newport - Croatian second seed Ivo Karlovic blasted 23 aces on Friday in defeating Germany's Dustin Brown 7-6 (7/3), 6-3 to reach the semi-finals of the ATP Hall of Fame Championships.
The 36-year-old from Zagreb, who lost in last year's final on Newport grass, seeks his seventh career ATP crown and second of 2015 after a triumph at Delray Beach in February.
Karlovic, ranked 24th, had lost his first two meetings with 80th-ranked Brown before winning their most recent prior matchup on his way to the Delray Beach title and dispatching him in 65 minutes on Friday.
Brown arrived at the tournament having shocked Spanish superstar Rafael Nadal at Wimbledon.
Next up for Karlovic on Saturday will be US fourth seed Jack Sock, who advanced when Czech qualifier Jan Hernych retired after holding serving in the opening game of their match. Sock won his lone ATP title this year on Houston clay.
Saturday's other semi-final pits Australian John-Patrick Smith against American Rajeev Ram, whose lone ATP crown came at Newport in 2009.