Kimi Raikkonen and Felipe Massa remained cautious about Ferrari's form ahead of the Malaysian Grand Prix despite topping the times in practice.
Raikkonen, whose team endured a dismal start to the season in Australia, emerged as quickest in the afternoon session, with Massa right behind in second.
The Finn, hit by KERS problems today, admitted he felt the car was competitive as long as it stayed reliable.
"This morning we had a problem with the KERS, which cost us a bit of time, but we managed to make up for most of it in the afternoon," said Raikkonen.
"We had felt that the situation here could be different to Melbourne, but it is still too early to say where we are up against the opposition.
"What we can be sure of is that when the car runs trouble-free, we are competitive. We hope we can do a good job in tomorrow's qualifying."
Massa, who also failed to score any points in Melbourne, was also cautious despite Ferrari's strong start to the weekend.
"The situation seems different compared to Australia, at least in terms of how the tyres operate," said Massa. "There is more grip and the softer tyres work well, even over a long distance.
"At the start of the long runs, I had a bit of understeer in the high speed corners and oversteer in the slow ones, but towards the end, the handling of the car improved continuously and I could set some great times."Clearly, looking at the timesheet today, there's a slight feeling of relief, even if it has to be treated with caution: we are very motivated and the whole team will be trying its best.