"They changed the master cylinder on the brakes last night after problems arose," Karthikeyan told HT over the phone from Italy. "I started to detect problems on the reconnaissance lap and then had no front brakes at the start of the race and had to retire.
"It was a shame, because a podium at least looked easy as my teammate (Luciano Bacheta) managed to finish second but what can you do?"
Karthikeyan had signed to race just in Monza, but admitted that a final decision to compete in the rest of the series will be evaluated and taken in the coming week.
"I would like to keep driving single seaters and this is a pretty competitive series," said Karthikeyan. "But there are some other options so I'll have to just wait and see for now."