Christian Horner has revealed that Electronic Control Unit (ECU) problem cost Mark Webber dearly in Sunday's Australian Grand Prix.
Racing at home, the Aussie was unable to retain his P2 from the grid as he got bogged down at the start when his McLaren-supplied ECU encountered problems.
Swarmed by rival drivers, Webber, who also lost KERS, fought hard to recover to recover to finish in sixth place.
"Mark's problems were hugely frustrating because it was an ECU issue and that is supplied by a third party," Horner said. "We lost all telemetry on the formation lap and then you can't do the preparation you need to at the start.
"That meant he was blind for the start and that ECU issue shut the KERS down as well. By the time we reset the whole system he'd lost the ground at the start
"It's something that they need to get on top of because there has been a lot of issues during testing."