The notoriously fickle South American weather came into play and Adrian Sutil clocked the ninth quickest time in both the practice sessions ahead of Sunday's Brazilian Grand Prix at the anti-clockwise Interlagos track in Sao Paolo.
His teammate Vitantonio Liuzzi was classified 17th in the morning and 16th in the afternoon after hitting traffic on his potentially quickest laps.
Light showers punctuated most of the day, making the timing for running crucial and Sutil did a decent job, completing 58 laps in total, making the most of the dry periods as he worked through his planned tyre and set-up evaluation for the track.
Liuzzi, participating in only his fourth race for the team this weekend, similarly worked through his scheduled programme with no major issues, completing 62 laps over the day.
"Today went OK with no major problems, just working through everything as usual with the tyre comparisons," Sutil later said.
"We didn't make any real changes on the car over the day as I was quite happy with the balance so we just waited until the grip improved on track and worked through the programme," said the German.