Lewis Hamilton denied Sebastian Vettel's claim Mercedes were sandbagging during Friday's practice sessions for the Russian Grand Prix.
Ferrari set the pace in Sochi, with championship leader Vettel following team-mate Kimi Raikkonen's example to go quickest in FP2.
Mercedes struggled to match the speed the Italian team got out of the ultrasoft compound, with Bottas (+0.670 seconds) and Hamilton (+0.709secs) some way off the German.
When asked if he thought the Silver Arrows were sandbagging, Vettel said: "Yes. I think they will be fine. It's a circuit that suits them so they will be strong.
"This looks like a Mercedes track. For sure they didn't show everything today and they didn't get a lap together, so the gap you see it's artificial."
However, Hamilton refuted such suggestions, insisting there are no positives to holding back during practice.
"We never sandbag. There's no benefit to sandbagging, ever," said the three-time world champion.
"I think Ferrari has done in the past but there is zero benefit for us to do so, we're trying to get the car to the optimum balance-wise and today's generally been a tricky day.
"I don't know why he would suggest that, it's just Sebastian trying to blow smoke our way.
"Really, those guys are just very quick."