McLaren racing director Eric Boullier says the team treated the Australian Grand Prix as a test session after a difficult winter.
Jenson Button managed to reach the end of the race, but he was the last classified driver in 11th position and two laps behind winner Lewis Hamilton.
Button's fastest lap was nearly 2.5 seconds slower than Hamilton's.
"We do race simulations normally during winter testing, and we couldn't do it. So it's good that we could do a race. We just used today as a testing session, to be honest," Boullier said.
The team had de-tuned the Honda engine to avoid more problems, and Boullier admitted McLaren had been very conservative in order to try to reach the end of the race.
"We are in the season, so we don't want to do anything stupid with the engine and blow anything up," he added.
"So we were very, very cautious, but we wanted to put some miles in our car and run the full race operationally."
Boullier concedes it will take time for Honda to catch up with Mercedes because the German manufacturer has been developing its engine for much longer.
"Mercedes has been developing the engine for more than three years and Honda 18 months, so that's a huge part of the answer. Mercedes has a good team in place.
"These engines has a lot of potential to unlock, so it may take more than a couple of years to catch up."