The Sauber F1 team as admitted that it was surprised to be quite so far off the pace in Monaco last weekend.
The team had successfully scored its first championship points of the season in the previous race in Spain. Pascal Wehrlein took eighth place in Barcelona despite incurring a five second penalty during the Grand Prix.
"We were surprised in Barcelona to be so competitive," Wehrlein's team mate Marcus Ericsson told Autosport magazine. "Everyone brought update packages [to Spain] and we only brought a rear wing."
But when it came to Monaco, both drivers hit problems. Wehrlein crashed after contact with Jenson Button, and Ericsson spun off after struggling with brakes and tyre temperatures.
The team had rolled out a more comprehensive set of updates for the race, and the Swede felt that this might have backfired on them.
"[For Monaco], we had everything else, with the new floor, bargeboards, turning vanes, everything," he said. "We were expecting after the Barcelona performance to be in the midfield fight."
That didn't prove to be the case, however.
"We were a second off the slowest midfield car in general all weekend," he sighed. "We were turning the car upside down all through the weekend. Going in different directions with the set-up to try and find something.
"When you bring an update, you need to tune the car, but it's tough to do that in Monaco," Ericsson added.
He added that it would have been better to have had the updates ready to roll out in Spain, which is a more standard track. The Circuit de Barcelona-Catalunya is used by teams for pre-season testing because it embodies many elements of the 'average' Formula 1 venue
Team principal Monisha Kaltenborn agreed with Ericsson that the sudden downturn in performance in the C36 had been unexpected.
"We know the car is peaky, but I wouldn't have expected to such an extent," she said. "It's strange that the car is so good in Barcelona and suddenly we come to Monaco and that happens."
The team is hoping to get on top of its problems with the latest upgrades in time for next weekend's Canadian Grand Prix.