Red Bull's Max Verstappen is unsure he'll be able to outpace the likes of Renault in qualifying at Sochi but the Dutchman is more confident in his race pace for Sunday's event.
Verstappen concluded his opening day of running at Sochi in 7th position, 1.529s behind pacesetter Valtteri Bottas, after two lively sessions in which the Red Bull charger struggled at times to keep his RB16 on its rails.
Verstappen had warned beforehand of the difficulties he expected to encounter in Sochi.
"We know that this track is not the best for us, but we were also trying out some downforce levels and seeing what is the best option," Verstappen said after FP2.
"FP2, yeah, I think we could have done a bit better, but again, we were testing a few things out. Some worked, some didn't, so it gives us a few ideas for tomorrow."
Apart from the unassailable Mercedes duo of Valtteri Bottas and Lewis Hamilton, Verstappen was preceded in FP2 by Renault's Daniel Ricciardo both McLarens and Racing Point's Sergio Perez.
"It will be tough in qualifying to be in P3," Verstappen said. "In the race, it looks a bit more competitive, so I'm happy about that, but there's still a bit of work to do to make sure we are still P3.
"So far today, [Renault] have been very competitive, and you never know who else.
"First of all we have to look at ourselves and make the right trade off with downforce levels as well, make sure the car is stable, and then I'm quite confident that qualy will be tight, but I think we can be in the fight."
Verstappen's teammate Alex Albon finished FP2 outside of the top ten, the British-Thai racer also forecasting a difficult weekend ahead given the progress enjoyed by Red Bull's direct rivals.
"The midfield have obviously made a big step since last year, so it's a bit more tight," Albon said.
"[The car] didn't feel bad, it's just everyone is very fast. We need to do some homework and find out where we can gain those little bits.
"On a track like this, honestly, it's just about looking after the tyres. It's so thermal here.
"You just need a really good balance, so if you're good in a short run, you'll be good in a long run. We're just missing a little bit in both."