Valtteri Bottas ended qualifying in Sochi just 0.095 seconds shy of poleman Sebastian Vettel , conceding to the Scuderia's current speed advantage.
The Finn out-paced team mate Lewis Hamilton again but the effort just wasn't good enough.
"Well I think it's pretty clear to see from the result, Ferrari was quicker today," Bottas said.
"We were close in the end, but not quite enough.
"To be honest, the whole weekend, they've had the upper hand and been able to extract much more especially from the ultra-soft tyre, and that's where we really struggled yesterday."
Bottas believes Mercedes is still a work in progress with improvements possible by tomorrow when the lead contenders line up on the grid.
"We made improvements for today, but obviously not quite enough still," Bottas added.
"Good team effort to get close, we're on the second row. As always, tomorrow is the day that really counts.
"I think a second row start here is not actually that bad a thing. It's a pretty long run into Turn 1."
GALLERY: F1 drivers' wives and girlfriends
Keep up to date with all the F1 news via Facebook and Twitter
Formula 1 is the pinnacle of speed, but former Haas charger and IndyCar returnee Romain…
The 2026 Formula 1 revolution is no longer theory — it’s a looming test of…
The great Niki Lauda would have celebrated his 77th birthday on this day, so it's…
Talk about a "burning" desire to get back on the grid. Yuki Tsunoda’s first appearance…
Adrian Newey’s vision for an Aston Martin dynasty is facing a brutal reality check as…
Aston Martin – 128 laps Mike Krack, Chief Trackside Officer “We have concluded our test…