Kamui Kobayashi set the pace for Sauber today at Jerez in Spain as testing continued in the countdown to F1 2010.
Kobayashi completed 103 tours in total, one of five runners to break the 100 marker, and in contrast to Wednesday the weather conditions were a lot better.
Indeed the track dried out quickly this morning and in the end his best effort was a 1 minute 19.950 seconds, which was set on his final lap. Pedro de la Rosa will now take over the C29 on Friday.
"It was a good day of testing as we managed to complete our programme," Sauber's head of track engineering, Giampaolo Dall'Ara summarised. "In the morning we did some aero tests. After the lunch break we concentrated on set-up and tyre evaluation.
"For most of the day we were running with a high fuel load prior to a run with a lighter car before the end of the session. For tomorrow the weather forecast is not really promising, but we will cope with what we get."
Sebastien Buemi meanwhile was 'best of the rest', less than a tenth off Kobayashi on a 1m 20.026s. Buemi concentrated on evaluating a few aero parts today, as well the assessment of different mechanical set-ups. He also tried out all three compounds of Bridgestone tyres.
"I am pleased with how the past two days have gone and although rain is never ideal, yesterday's damp conditions meant we could try the wet weather tyres," stated the Scuderia Toro Rosso pilot. "Today, in the dry, we were able to do a lot of laps, as the car ran reliably. We tried various set-ups and ran with different fuel loads, so we are beginning to get a better understanding of STR5 in general."
Jenson Button was third for McLaren and declared himself much happier with the seat and installation following his day at the wheel of the MP4-25.
He began proceedings with a continuation of the early-morning aero mapping started yesterday. Then after a successful number of aero runs, he switched to finding suitable mechanical and aero set-ups, before focusing on longer running, including evaluating tyres on a number of varying fuel-loads in the afternoon.
He had to make a precautionary stop just before the day's end when a warning light came on in the cockpit, but that was his only problem.