Sebastien Buemi was left lamenting his lack of running in Friday's practice sessions for the Bahrain Grand Prix after failing to complete a timed lap in the afternoon.
The Toro Rosso driver was forced to watch from the sidelines all afternoon as the team worked on an unspecified problem at the rear of his car.
Buemi had completed 13 laps in the morning on his way to the 14th quickest time.
"I'm glad I spent plenty of time driving this track on our simulator, as I did no timed laps this afternoon, because of a problem with the car," said Buemi. "The changes to the track were much as I expected and there is a big bump at Turn 6.
"There are no passing places in the new section, but it makes for a longer track which is more interesting to drive.
"You need to be competitive in Sector 2 for a good lap time, which means you must compromise between needing high downforce for this slow part, while less downforce will make you quicker in Sectors 1 and 2.
"Fortunately, we will be able to analyse Jaime's data and start from a better position tomorrow. However, when you miss most of Friday testing, it doesn't make life easy. But we have to live with that and concentrate on tomorrow."
Team-mate Jaime Alguersuari, on the other hand, enjoyed a solid day and posted the 16th quickest time of the afternoon session.
"A good day in which we did all the laps we could, trying many different things," he said. "I think we improved during the day, but it's hard to know where you are with the wide range of fuel loads being used. I feel the performance is there and if we have another nice day tomorrow, then we should be able to get the most out of the car.
"The track was very green this morning, but it started to rubber in this afternoon. The new section is nothing special and very slow, but I knew that from working on the simulator, which meant I already had an idea where to turn in and where were the braking points."