Ivo Karlovic made a second-round exit at the Hall of Fame Tennis Championships as four seeds departed on Wednesday.

Karlovic – a three-time finalist in Newport and the 2016 champion – suffered a 7-6 (8-6) 6-7 (4-7) 6-2 loss to Dudi Sela.

The big-serving Croatian sent down 18 aces, but he also produced 15 double faults to lose at the ATP 250 event.

Sela will face Steve Johnson, who was one of just two seeds to progress with his 6-3 6-1 win over wildcard Christian Harrison, in the quarter-finals.

Seeds Mischa Zverev, Matthew Ebden, Gilles Muller and Denis Kudla made surprise exits.

Zverev was edged by Vasek Pospisil 4-6 6-3 7-5 and Ebden – last year's runner-up – went down to Tim Smyczek 6-3 6-3.

Muller, the runner-up in 2016, was beaten by Marcel Granollers 7-5 7-6 (7-4) and Kudla suffered a 4-6 6-3 6-4 loss to Ramkumar Ramanathan.

Top seed Adrian Mannarino had no such issues, overcoming Australian Jordan Thompson 6-2 7-6 (7-4), while wildcard Jason Jung brushed past 2013 champion Nicolas Mahut 6-4 6-4.