Lotus believes its below-par performance in Singapore owed more to a scrappy weekend on track than any fundamental weakness with its car.
Trackside operations director Alan Permane reckons the outfit never bounced back from a difficult Friday when new aerodynamic parts did not work as expected.
"We definitely didn't get on top of the car this weekend," Permane told AUTOSPORT after seeing Kimi Raikkonen and Romain Grosjean come home sixth and seventh in the race.
"We had a very poor Friday, but we understood pretty much where we'd gone wrong. We recovered an awful lot of it, but didn't get it perfectly right."
He also hinted that both drivers were partly responsible for their positions in the field after a disappointing performance on Saturday.
"Neither driver had a good qualifying session," he said. "Kimi went slower in Q2 on new tyres than scrubbed - and was a little bit off everywhere over the lap. Romain should've been good for fourth or fifth on the grid, not eighth.
"Then in the race we were very unlucky with the safety car for Kimi. We pitted him, and the safety car came out at that moment, so ruined our chances of beating Rosberg.
"That said, I don't think we could have raced [fourth placed] Paul di Resta, for example."
Despite its difficult weekend, Raikkonen's result was enough to keep him third in the drivers' championship.
The Finn is 45 points behind leader Fernando Alonso with six races remaining.