Alexander Rossi said a small mistake resulted in a big repair job following his first practice session with new team Manor at the Singapore Grand Prix.
Rossi crashed towards the end of first practice after losing the rear of the car in Turn 18, resulting in the right-hand side suspension needing to be patched up before FP2.
"It was good apart from 30 seconds of it," he said. "It was quite good, I got up to speed very quickly. I felt comfortable in the car straight away, I made a small mistake in FP1 which hurt us a bit so we lost time in FP2 and didn't get to do our long runs which has put us on the back foot. Fortunately there's another session tomorrow.
"We were trying a couple of new things and I didn't really expect the change to be as extreme as it was. It was a small mistake but a big consequence because of where it was. But such is life sometimes. The team has moved on from it, I've moved on from it. They did a great job to get the car back out for FP2. We just need to learn from it.
"I was quite upset to be honest, it's not what you want to do in your first session."
Rossi said he was still confident for the rest of the weekend but that there would be a lot of work to do in final practice.
"FP3 will be very busy, we'll try and do as many laps as we can. As many laps as we can do is great. Fortunately, I settled into the car quite well. I don't feel like I need laps to go quickly round here. I just need laps to under stand how tyres work and how we manage it."