The Ferraris have impressed quickly at the Bahrain Grand Prix, with Felipe Massa setting the fastest time in the first practice followed by teammate Fernando Alonso on Friday.
Massa, twice a winner of the Bahrain GP, was 0.077 seconds faster than Alonso, who won the Chinese GP last weekend. Mercedes driver Nico Rosberg was 0.134 behind in third followed by Red Bull's Sebastian Vettel, who was 0.303 off the pace.
Vettel's teammate, Mark Webber, managed seventh fastest while Lotus driver Kimi Raikkonen was ninth.
Lewis Hamilton, who won the pole in Shanghai and earned his second consecutive podium finish, was down in 13th in an otherwise uneventful practice in hot and dry conditions.
The race has been overshadowed to some degree by the political crisis in the divided Gulf country.
While the circuit has been quiet, daily clashes have taken place in nearby Shiite villages between pro-democracy protesters and riot police. Hardline protesters hope to embarrass the ruling royal family with increased violence, while more moderate protesters, who support the race, merely want to highlight their demands for a greater voice in the country.
Rights groups, meanwhile, have condemned the race going ahead amid allegations of crackdowns and widespread arrest of government opponents.
Teams and drivers have mostly remained silent on the political crisis, and the FIA, the governing body of world motor sports, has endorsed the race. It said the Bahrain GP should proceed "following assurances from the local promoter and the authorities that security, their responsibility, will be guaranteed for all participants."
"The FIA and FOM also strongly believe that sport can often be a force for good and that the staging of the grand prix in Bahrain will come some way in helping soothe some of the issues which have been raised in the media," the FIA said in a statement.