JOIN USSomdev, who is India's top-ranked singles tennis player, put up a brave face against Karlovic by holding his serves in the first set but failed to keep the momentum going as he was broken in the last game to concede the lead at the hardcourt ATP event last night.
Somdev, who hit 70 per cent of his first serves, was also broken twice in the second set.
The 33-ranked Karlovic, who leads the number of aces on ATP Tour this season, fired overall 14 aces -- 11 in the first set -- and had 63 per cent accuracy in his first serves against the Indian qualifier.
"It's really hard to break his serve when he is serving that well," said Somdev.
"I was doing well and then he got the break. Momentum went his way after that," he added.
Somdev, who carved out "the biggest win" of his career by defeating sixth seed and World number 15 Croatian Marin Cilic in straight sets in the previous round, did not seem to be disappointed at his prequarterfinal loss though.
"I feel like the summer started on the right note," said the Indian who jumps about 10 spots in the ATP rankings to be 143rd.
Karlovic will now meet top seed and World number 5 Andy Roddick in the quarterfinals after beating compatriot Sam Querrey 7-6 (7/4) 6-4.
Roddick, who won his 500th match yesterday, seeks a 29th career crown.