Bottas: Upgrade failures key to Williams' 2016 downfall

Williams was the third-best team in F1 in 2014 and 2015, but slipped down the order in 2016, losing out to Force India in the battle for fourth in the second half of the campaign.

For Bottas, the author of the Grove-based team's sole podium in 2016, the balance of power was tipped towards Force India after the European leg of the season, when Williams' upgrades didn't work out as intended.

"It was around mid-season," Bottas said. "The European season, the end of the European season, the upgrades we hoped would bring us positions were not that bad compared to now - but then a couple of the big upgrades didn't turn out to be that much better.

"If you start solving those problems, it takes time - and that costs time in the next year car's development. Then the team opted to focus on next year and that was the turning point. The failure of upgrades."

The Finn insisted, however, that he had no qualms about the decision to focus on 2017.

"Sure it's tricky to, for example, be not able to get to Q3 in normal conditions, it's tough. And when in the race you don't have the pace, it can be pretty challenging mentally - but it's normal in Formula 1.

"It's where you are as a team and, no matter what, as a driver you need to squeeze out everything from the package and have a good race. It's tricky but I really hope it pays off next year.

"Now I've seen more stuff from the new car and the regulations and how many changes, I'm actually glad we switched focus early. I'm sure there's no harm chasing it early for next year. Hopefully we get better results next year."

Bottas warned, however, that Williams needs to address the fact its upgrades had underdelivered, as strong in-season development is expected to be crucial in 2017.

"Definitely something has to change. We understand that something has been wrong in terms of the upgrades, how we measure things, that they should be better in theory but then they are not – which was not the case last year or the year before.

"So something has not worked correctly, and definitely that is a big thing to improve, especially next year when the cars are new and the rate of improvement of everyone is going to be big.

"I think next year, from first race to last race, is going to be a massive development and if you're developing less than the others, then it is going to be tricky."

Additional reporting by Jonathan Noble