Sauber technical director James Key admitted that the team's car was not quick enough to stay in contention for a podium finish in the Canadian Grand Prix once the track dried.
Kamui Kobayashi ran second in the wet part of the race, but faded to seventh at the finish as conditions improved.
"Kamui did well to make a bit of progress initially, and we felt the race pace could be better because we'd been on higher downforce all weekend - anticipating weather conditions to a certain extent," Key told AUTOSPORT. "He did pretty well in the wet and actually we were quite competitive.
"Unfortunately we were in a situation where we couldn't use the DRS because we were at the front of the back, and our straightline speed wasn't good because we were on the higher downforce level. We never really got an opportunity to have a go back.
"Our dry pace wasn't very good here, and I think when the dry tyres came in, we suffered a bit. On the dries, it hasn't been our track, so we lost out."
Key said he never had high hopes for Montreal, but still found the degree to which Sauber struggled in the dry a disappointment.
"It could've been worse," he said. "The pace was disappointing in the dry.
"We kind of know what it is - it's a combination of things. But it was a bit worse than I thought it would be here. It's not our track at all.
"So to come out with a seventh place, we can't complain at all. It's just that it could have been a bit higher if things had worked in our favour in the race."