Kamui Kobayashi was sorry the poor weather conditions did not allow him to do more running in his return to Formula 1 action on Friday.
The Japanese driver was called to stand in for the unwell Timo Glock in the second Toyota, although the German is expected to be back in the cockpit for tomorrow's practice and qualifying.
Kobayashi managed 16 laps in the morning, but just seven in the rain-hit second session.
"I only heard I would be driving today at 8:30 this morning when I was on my way to the circuit; it was a bit of a surprise because even though I knew Timo was sick, I wasn't expecting this," said Kobayashi. "It was a really good opportunity for me but the conditions were pretty bad and I didn't get a lot of laps in the end.
"I had quite a good run in the first session and I was trying to improve step by step. It was important not to make any mistakes because I wanted to complete as many laps as possible, for me and the team.
"I wasn't pushing 100% due to the wet conditions but still the lap times were pretty good, especially considering I don't have much experience of this track and haven't driven here for six years. The car feels like it has improved a lot since I last drove it in February. It's difficult to judge in the wet but I was really impressed with how much development has been done in that time."
Teammate Jarno Trulli was left hoping for improved weather tomorrow after an almost useless day.
"There's not much to say after that," he said. "Unfortunately for all our Japanese fans the weather severely limited our running today. I hope we have better weather tomorrow so we can put on a better show for them. The car didn't feel too bad in the wet but it is difficult to comment too much on it because of the conditions."