Former world champion Kimi Raikkonen clocked the best time on the final day of Formula One testing Friday but Ferrari's Felipe Massa remained the only driver to break 1min 18sec all week.
Raikkonen, the 2007 world champion, took his Lotus to a time of 1min 18.148sec off 83 laps with Force India's test driver Jules Bianchi, eager for a full-time season drive, in second spot on 1:18.175.
Triple world champion Sebastian Vettel was third fastest in 1min 18.565sec after completing 96 laps in his Red Bull.
Raikkonen and Bianchi also had the honour of clocking the week's second and third best times, but neither were able to better Ferrari driver Massa's time of 1:17.879 set on Thursday.
"We continued our work from Thursday and made some good progress," said Raikkonen, who will attempt to build on his week's work at the next test session in Barcelona from February 19.
"We're at the top of the timing monitors, but that means nothing in testing. Our focus has been testing parts on the car, but I've been able to get the set-up more to my liking.
"For sure there's more work to be done in this area, but that's what we're here for. The car feels strong and we seem to have a good idea of where we're going with improvements. Let's see what happens in Barcelona."
Friday's final day was extended by 30 minutes after repairs were needed to fill in a hole which had appeared in one of the curves at the Jerez track.
Vettel, who drove 96 laps, said he had been impressed by the car's reliability.
"I think for the whole team it's been quite a good test," said the German.
"No problems in terms of reliability and we did a lot of laps, so I'm quite pleased with the results. I feel a bit better than last year. I think we had some issues with reliability then, so it seems we have done our homework well."
Vettel also shrugged off the delay to fix the pot hole, insisting it was an indication of the speeds being done by the drivers.
"Everyone is on the limit here, running wide, using the maximum amount of track and the kerbs and unfortunately it started to break up," he said.
"But the circuit did a very good job over lunch to get everything sorted and gave us an extra half hour at the end, so no real problem."