Romain Grosjean admitted that Lotus are nowhere near where they expected to be at this stage of the season, after the Enstone team languished near the back of the grid after Friday's free practice in Bahrain.
The controversial twin tusk Lotus E22 have had a variety of issues throughout the season so far, although Grosjean and his team-mate Pastor Maldonado did manage to complete 103 laps at Sakhir on Friday.
Maldonado was the quicker of the two, but he was about three seconds off the pace set by Lewis Hamilton in his Mercedes in both of Friday's free practice sessions.
Following Friday's practice session, Grosjean said that they were "miles off" where they wanted to be this week, even though the majority of the reliability issues seem to have been fixed.
"We just need more time to understand why in the windtunnel the car looks good and on the track it's not as good as we hoped," he told Autosport in Bahrain on Friday.
"Mercedes has a bit of an advantage but we are miles off where we would like to be.
"Red Bull is maybe not the best example because they have an outstanding car, but Toro Rosso is far ahead of us and we should be capable of being in front of them.
"Today we were slow. I don't know if it's track related. I'm sure we could use the Pirelli tyres better. It's not the best weekend so far.
"We have seen we have a quite sensitive car to wind conditions and we are not yet exactly with our baseline set-up in the best region for aerodynamics. The engineers are looking into it."
The Frenchman added that he feels like Lotus have taken a step backwards after he finished a credible 11th in Malaysia last week and admitted that he isn't comfortable driving the car at the moment.
"The car is quite difficult to drive at the moment, to be honest," Grosjean added.
"The brake-by-wire is still not perfect, rear downforce is not the best strength right now. It just makes everything a little bit harder."