Jolyon Palmer expressed confidence that Renault has repaired the problem which he feels has held him back across the previous couple of races.
Palmer slumped to 22nd and last during the Chinese Grand Prix, while he lagged behind Sergey Sirotkin and Kevin Magnussen during Friday's practice sessions at the Sochi Autodrom.
Palmer qualified in only 18th place for the Russian Grand Prix but was able to get within a tenth of a second of team-mate Magnussen and was relieved by his progress.
"Today the car has been really good," he said. "I think we’ve found the problem that’s been hurting me the last couple of Grands Prix.
"We’ve changed something and it’s working well so it’s good to be back on track!
"I’m pleased because I can now demonstrate what I can do as a driver whereas before it was frustrating.
"We’re not super quick as a team but I’m happy with the car and I think we can look forward to a good race tomorrow.
"Our race pace tends to be better than in qualifying; we should be able to move forward quite quickly, we’ll definitely aim to challenge the guys in front of us and take any opportunity on offer."
Magnussen will start from 17th place but rued his inability to get the Super Soft tyres working effectively.
"It wasn’t a brilliant qualifying lap from me and we struggled to get the tyres into their correct operating window, so not a perfect set-up for the car either," he said.
"FP3 earlier in the day was much better for us as we were able to get a more even balance with the front and rear tyres working well together, however qualifying proved to be more of a challenge."