American second seed James Blake suffered a shock defeat at the San Jose Open when he was upended 6-7, 7-6, 6-4 by world number 103 Ivo Karlovic of Croatia on Thursday.

Blake served for the second round match at 5-3 in the second set but was broken, lost the tiebreak 13-11 and Karlovic went on to break again in the 10th game of the decider to win the contest.

Karlovic, who hammered 29 aces, smashed a forehand return for a winner on his third match point to set up a quarter-final against another American, fifth seed Mardy Fish.