Both Kevin Magnussen and Jolyon Palmer suffered a disrupted day of running during practice for the Monaco Grand Prix after encountering separate incidents.
Palmer brushed the barriers exiting Tabac during the morning session and was unable to complete his scheduled running, with repair work also impacting on his afternoon run plan.
Magnussen, meanwhile, ran wide at Anthony Noghes and hit the wall, ending his afternoon prematurely.
Magnussen placed 17th overall, three positions ahead of team-mate Palmer, who was edged out by both Sauber drivers.
"It wasn’t the best day for us," admitted Magnussen.
"We thought we’d made a step forward at the Barcelona test but on this track we didn’t have the car we expected.
"The latest spec engine certainly delivered and it’s a decent improvement, but we still have work to do on the set-up and, of course, finding more downforce."
Palmer nonetheless drew encouragement from tweaks made to the RS.16.
"We discovered a lot about the direction we want to go with the car and I think we can move forward quite well," he said.
"The day didn’t start out all that pleasantly; the track was slippery and I made a mistake in Tabac; I just had a small bit of oversteer while pushing the limit and I found the wall.
"But we were trying something that we were doing in testing last week and, even if we weren’t quick, we took a great deal from it which is good."