Bahrain GP Williams F1 driver Bottas's first back-pain-free event

The Finn had to sit out last month's Australian GP after suffering what Williams described as "a small tear in the annular part of a disc".

He was cleared to return for the second round of the season in Malaysia having made changes to the position of the car's pedals and seat, but had continued to encounter some mild discomfort prior to this weekend.

"I don't feel anything now while driving, this is really the first weekend that I feel nothing," said Bottas when asked by AUTOSPORT about his back.

"The new driving position I have is a really good step forward, it's much more comfortable.

"I'm not worried [that it could happen again]."

Bottas qualified fifth for the Bahrain GP, eight tenths off Lewis Hamilton's pole position time, and admitted that he had been hoping to challenge Ferrari drivers Sebastian Vettel and Kimi Raikkonen.

"With what we saw from practice, I thought we maybe could be fighting for the second row but Ferrari was quicker today," said Bottas.

"The run in Q3 was a nice clean lap, my best lap of the weekend, but they are still just that step ahead in qualifying ad we know that in the race they could be [ahead] a bit.

"We will do everything we can tomorrow, but we know it's not going to be easy if we want to gain any positions."

Team-mate Felipe Massa had looked set to outqualify Bottas, but lost time in the final sector on his Q3 lap and ended up sixth, almost four tenths slower.

"I just went sideways at the last corner, maybe because I was trying too much," said Massa.

"So I just lost time on Q3 after a very good Q2.

"I tried to save a set of tyres in Q3, and the lap on old tyres was not very good so maybe I was not 100 per cent on target to do the perfect lap in Q3."