Ferrari boss Maurizio Arrivabene has called for an end to speculation about Kimi Raikkonen's future.
Finn was one of four drivers to pit early for intermediates and the decision backfired, with the rain not intensifying further for another four laps.
Sebastian Vettel said Mercedes were "in a different world" after Lewis Hamilton qualified a second one second clear of the fastest Ferrari at the British Grand Prix.
Finn says out-qualifying team-mate means little when Ferrari can only finish fifth and sixth behind both Mercedes and Williams.
Sebastian Vettel is under no illusion that Mercedes will be hard to beat at Silverstone this weekend, despite finishing ahead of Lewis Hamilton in Friday practice.
Finn says there is still more to come after struggling with the hard compound during the Friday afternoon practice session at Silverstone.
Vettel denies his team-mate is going through a "negative period", reminding critics the Finn is a former world champion.
Ferrari is yet to take up option on Finn's contract to extend his time at Ferrari into 2016 but Raikkonen says speculation about his future never changes.
Brazilian thinks his former team-mate is starting to feel the pressure of expectations at Ferrari.
Finn makes his second appearance in a row, driving the Ferrari Fernando Alonso nearly took to the 2010 world championship up Goodwood's famous hill climb.
FIA confirms Mercedes and Ferrari have not been using 'trick oil' systems to gain an advantage over their rivals after detailed investigations of both teams at Canadian Grand Prix.
Ferrari boss insists the team's focus is still on beating Mercedes, "not in 2020 - this year".
German picks up where he left off during Austrian Grand Prix by ending the test over eight tenths clear of Ferrari's Esteban Gutierrez.
Finn clocked a 1:10.029 in the FW37, while Nico Rosberg finished the morning third for Mercedes and Fernando Alonso managed just 17 laps in the McLaren MP4-30.
Mercedes junior keeps the world champions top of the timing screens after day of testing hampered by rain at Red Bull Ring.
Maurizio Arrivabene wants Ferrari to run full fuel during Friday practice sessions to gain an accurate comparison to Mercedes' race pace.
Maurizio Arrivabene has named the areas in which Kimi Raikkonen will be judged ahead of a decision on the Finn's future later in the year.
Convinced Ferrari is closer to Mercedes than Austria result suggests despite second race in a row which saw neither driver make the podium.
Kimi Raikkonen could not explain the reason behind his collision with Fernando Alonso at the Austrian Grand Prix, but appeared unruffled by the dangerous situation it left him in.
Spaniard ended up on top of former team-mate's car after first-lap collision on the exit of Turn 2.
German qualified third as Mercedes locked out front row but thinks Ferrari's race pace this weekend is need for improvement.
Massa nearly ran over Ferrari boss in pit wall but managed to stop short - something the pair shared a joked about later on during Friday practice.
Finn only completed one lap on the option tyre,f while Ferrari team-mate's Sebastian Vettel's own run on super-softs ended prematurely.
Ferrari driver returned to the garage at the end of FP2 with a gearbox issue; says it was unrelated to FP1 stoppage.
Kimi Raikkonen has hit out at stories claiming he would accept a pay cut in order to be kept on at Ferrari next year.
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