Murray beat Karlovic 7-5, 6-7 (5), 6-2, 7-6 (4) Thursday to reach the third round, with  the hard-serving Croat being foot-faulted on key points.

"I don't know what to say, but it was a little bit outrageous," Karlovic said. "After this match, the whole credibility of this tournament went down for me."

One foot-fault was called in the final tiebreaker, while several others were made in the later stages of games. Karlovic said he moved his feet back further behind the baseline to avoid more foot-faults, but they kept being called.

"Right now I'm angry about it ... because I don't expect it here," Karlovic said.

Murray said he wasn't sure whether the calls were correct but that "if he wasn't foot-faulting then he has a right to be upset, because there was a lot of them. But if he was, then you can't do it. It's not allowed."

While Karlovic won the second-set tiebreaker, he said the foot-faults had a decisive effect on the final result.

"If these 10 points, I win, who would have won?" he said. "You do the math."

Earlier on Thursday,  Croatian qualifier Mirjana Lucic knocked-out the ninth seed Marion Bartoli of France (6-4, 6-3). Lucic was a semi-finalist in 1999 before her career and personal life went into a tailspin. But, at 30, she is enjoying a new lease of life on the tour.