Rio Haryanto was left to rue a lack of long run data after he crashed out of Thursday's second practice session for the Monaco Grand Prix.
Haryanto was on a flying lap on Ultra Soft tyres when he lost control approaching the Nouvelle Chicane and spun into the outside barriers, before coming to a halt in the run-off.
Haryanto was unable to complete the remainder of the session and will thus head into Saturday's final practice with limited data in terms of long run pace.
"I feel alright, just a bit unfortunate that we couldn't finish the run programme," he said.
"Looking at the car damage, it isn't too bad, it's quite minor.
"I just lost it because it's quite bumpy and tricky. I was on the Ultra Soft tyre on my second pushing lap, and I just lost the rear as it snapped.
"It just went into the wall. It's a shame that happened, because we didn't get to do a long run but looking at the performance today, we're not that far from the Sauber."
Haryanto was nonetheless able to finish the session in 21st place, in front of team-mate Pascal Wehrlein.
"Pascal shouldn't be underestimated," said Haryanto. "It's his first time here and he's doing really well.
"I have an advantage in knowing the track better than him but so far, I'm quite happy with my performance and making use of my experience like in GP2 and bringing it to F1."