VALTTERI Bottas had mixed emotions after the first day of testing at Catalonia’s Circuit de Barcelona.

The 26-year-old completed 80 laps in the Grove-based Williams Martini Racing, setting the fourth fastest time of the day with 1min 26.091secs.

Bottas was just over a second slower than Ferrari’s Sebastian Vettel who set the pace.

Williams encountered a few problems with Bottas staying in the pits for longer than expected, but the Finnish driver remained philosophical.

“It’s always very nice to be back in the car and it’s nice to feel that we have made improvements, but it is way too early to say anything more than that,” he said.

“We were focusing on different kinds of tests with the chassis, and some aerodynamic tests so mainly longer runs.

“We had a few problems but that’s testing.

“First impressions of the new car are good and I think we have fixed many issues from last year.

“However, like I said before, it’s just too early to say where we are against the others.”

Chief test and support engineer, Rod Nelson, echoed Bottas’ thoughts.

He said: “We had a slightly mixed day.

“We had a few niggling little issues that kept us in the garage for longer than we wanted to be there, but we’re still learning about the car so that’s not unexpected and we were able to work through them to continue our programme.

“Valtteri has been complimentary about aspects of the FW38 which is good start.”

The first test came just days after Williams launched their car for the 2016 Formula 1 campaign.

After finishing third in the constructors championship in the past two seasons, founder and team principle, Sir Frank Williams, knows it will be tough to maintain their place among the elite.

He said: “We have started to cement our position back amongst the front running teams.

“Staying where we are will be a challenge in itself, but we are determined to keep improving.”

Bottas and Felipe Massa will be behind the wheel for a third successive season and Williams added: “We have a very stable team.

“We have a busy couple of weeks of testing coming up to learn more about our package but I’m confident that our hard work over the winter will stand us in good stead.”