Red Bull drivers Sebastian Vettel and Mark Webber admitted they were hoping for more track time during practice in Bahrain on Friday.
Vettel managed 35 laps in total over the two sessions, but the German said more running was needed, as he felt the car was still far from what he wanted.
"Unfortunately we didn't get a lot of running today," said Vettel, fifth quickest in the afternoon.
"The track was still green this morning, so everyone was just checking their cars. In the second practice I had have the brakes changed and Mark couldn't do the whole session, so it wasn't ideal.
"I would have liked more track time, but it's not Christmas and we're not given things for free. We have a lot of work to but we know where we need to improve, so we will work on that."
Webber covered only 12 laps in the afternoon after having problems with his car's gearbox.
"Not such a good day and not enough mileage," said the Australian. "We missed out a bit this afternoon; I had a gearbox problem, so the team made a precautionary stop with the car which ended P2 early.
"We'll have to regroup and get what we can out of today - we'll be focusing on qualifying in tomorrow's practice. We still learnt some stuff today and Seb looked at the tyres. You can already see that it's going to be bloody competitive this year, it's going to be a good fight out there."