Valtteri Bottas opted not to run in the second of Friday's two free practice sessions at the Japanese Grand Prix in a bid to save tyres should the day's wet weather prevail into the weekend.

The Finn had rounded out the top ten on the morning timesheets but, with little to learn from running in the wet, and concerned that his Pirelli rubber was wearing a little too fast for his liking, he took the decision to observe the afternoon's action from the Williams garage.

"It wasn't a great Friday for us," Bottas sighed, "We did just a couple of runs in FP1 and, by the end of it, the two sets of tyres I had used were already in very bad condition, so we couldn't have learned anything about the car if we'd run with those sets in the afternoon. That's why we decided not to run in the afternoon because, in case there's more rain coming during this weekend, we don't want to run out of wet weather tyres. It was a shame."

Related Articles

While Bottas sat out, team-mate Felipe Massa continued to pound around the Suzuka circuit, albeit in pursuit of an eventual 16th place as the rain returned to slow progress in the second half of the 90-minute session. Despite that, and his own absence, Bottas was encouraged by some of the work that Williams completed during the two sessions, although he admits that it just one step in the right direction should there be more wet running over the remaining six races of 2015.

"We are struggling with the balance and, in FP1, we split the cars with very different set-ups, then swapped set-ups for the second runs," he explained, "I think we found something that could help us in the future, but it was not a breakthrough, though. We still have a few things to learn in the wet but I think we improved the situation slightly today as there was quite a big gap between the two set-ups when Felipe and I were running in the same conditions. When I went out in FP1, with old tyres, I could improve my previous time, so there's a step forward in the new set-up."

After a tough weekend for all the Mercedes-powered runners in Singapore, Bottas is also confident that the Three Pointed Star will be more competitive in Japan, especially if the conditions change for the better.

"I'm sure it will be different from last week, if it's dry, especially," he confirmed, "I think we should be more competitive, so it should be okay."