In Bahrain last week the former Ferrari driver posted the fastest time of the four-day session: 1 minute 33.2458 seconds, in the final testing period before the season-opening Australian Grand Prix in Melbourne on March 16. (Agencies)
It was an equally heartening session for 16-times world champions Williams, who had one of their worst campaigns last season.
Boasting a history encompassing nine constructors' titles and seven Formula One drivers' championships, Williams managed just five points last term and finished ninth in the standings.
But Massa's form in the Gulf has given both driver and team hope ahead of the 2014 season.
"I think it's a new time, everything is new, there is a big change for the rules and for everybody," Massa said as Williams unveiled leading drinks brand Martini as its new main sponsor in London on Thursday.
"For me I think it was the right time to change and start something new," said Massa, who finished runner-up to Britain's Lewis Hamilton in the 2008 World Championship.
“I'm really happy with the work up until now," added Massa, who finished eighth last season.
"From what I've seen inside the (Williams) team, how people work, the motivation, the development of the car day by day inside the factory it's really positive.
"I'm very happy and 100 percent motivated and looking forward to having a good season. The Championship is long; it's difficult so I think we always need to keep our feet on the ground."
Massa explained how changes in Formula One regulations had made all the cars on the grid, including the Mercedes-powered Williams FW36, harder to drive.
"With the new regulations, it is a big challenge, there's more torque from the engine but at the same time we have a bit less down force due to the regulations, so the cars are a little trickier to drive," he said.
Team principal and founder Frank Williams added, "2014 is going to be a fascinating season, with regulation changes of this scale often shaking up the grid and creating opportunities for teams to make a good step forward.”
"Over the winter we have proved our ambition by making a number of positive changes; we welcome a new driver pairing (Massa and Valtteri Bottas), new senior technical personnel, and a number of new commercial partners for 2014," he said.
Among those new commercial partners is Martini, whose racing 'stripes' have featured prominently in 24-hour sportscar events in recent seasons, but whose connection with Formula One dates back to the 1970s and included a two-year spell as a backer of Ferrari from 2006-2008.
"It will be great to see the distinctive stripes of Martini Racing return to Formula One once again in unison with Williams", said Williams.
Last season Williams only managed to collect points at the Hungarian and United States Grand Prix.
“Last year was a difficult year," said Finnish racer Bottas. "I think we learnt a lot and I think we have a much better starting point for this year."
In Bahrain last week the former Ferrari driver posted the fastest time of the four-day session: 1 minute 33.2458 seconds, in the final testing period before the season-opening Australian Grand Prix in Melbourne on March 16.