Having established a "good platform" on Friday, Sebastian Vettel says overnight improvements to the car could make the Bahrain GP win "possible."
The German, who already has one victory to his tally this season having triumphed in Malaysia, joined the tussle at the front in Friday's practice.
Second to team-mate Kimi Raikkonen in FP1, Vettel finished the day fourth fastest as Nico Rosberg and Lewis Hamilton set the pace.
But despite once again falling short of the Mercedes pairing, Vettel is refusing to rule out winning Sunday's Bahrain GP.
He told Sky Sports News HQ: "It's always possible.
"I think it's most important that we feel good inside the car and then we have a good platform to work from. Obviously now overnight we try and improve and go from there."
Vettel was also encouraged by Ferrari's one-lap pace at the Sakhir circuit.
Although he struggled to get in a clean lap, his best time of 1:35.277 was just 0.630s off Rosberg's P1 time.
"My last lap, my last flying lap, was not perfect. Up to the last corner maybe it was but nevertheless I think it looks pretty close.
"But we know that Mercedes is turning up their engines for qualy so I'm sure they are still a bit ahead. The closer we can get, though, the better it is."