Second-seeded Croatian Ivo Karlovic took a positive step toward defending his title at the Hall of Fame Open on Wednesday with a 6-4, 6-4 victory over American Denis Kudla in the second round on the grass courts at Newport, R.I.
Karlovic recorded 16 aces and broke Kudla on three occasions to successfully bounce back from a near-two-week absence following his first-round loss at Wimbledon.
The 38-year-old advances to a quarterfinal clash with German Peter Gojowczyk, who rallied to a 2-6, 6-4, 6-4 victory over Russian Konstantin Kravchuk.
Gojowczyk's countryman, Tobias Kamke, also advanced to the quarters with a 7-6 (5), 7-5 upset of third-seeded Frenchman Adrian Mannarino. Kamke has enjoyed success in Newport, advancing to the tournament semifinals in his lone appearance in 2011.
"I had to adjust a little bit (from the first round), because my second-round opponent likes to counterpunch," Kamke said. "I like to hit the balls pretty hard, but today I tried to mix it up and not give him too much pace because I know he plays very, very well. It worked out OK."
Top-seeded American John Isner faced little resistance in his opening match with a 6-2, 6-4 triumph over Australian qualifier Sam Groth. Isner, who won this tournament in both 2011 and 2012, notched 13 aces to dismiss his foe in 61 minutes.
Isner advances to face countryman Dennis Novikov, who breezed to a 6-3, 6-2 win over Canadian Frank Dancevic.
Fourth-seeded Frenchman Pierre-Hugues Herbert saved 11 of 15 break points to emerge with a 7-5, 2-6, 6-3 victory over Spaniard Adrian Menendez-Maceiras.
Australian qualifier Matthew Ebden continued his strong tournament with a 6-1, 7-6 (2) victory over sixth-seeded Slovak Lukas Lacko. Ebden ousted wild card and two-time Hall of Fame champion Rajeev Ram 6-1, 6-4, on Tuesday.
Also on Wednesday, American Bjorn Fratangelo outlasted Australian Akira Santillan 7-6 (3), 3-6, 6-1 in one hour and 49 minutes.