Massa went through a revolving door over the winter, heading into retirement before turning back and extending his stay with the Grove-based outfit
It has proven a worthwhile decision based on his performance over the past week in Barcelona which Williams performance chief Rob Smedley puts down to a symbiotic relationship between car and driver.
"I think it suits his driving style perfectly really," explained Smedley.
"The cars that we have got now are much more akin to the cars when he had his more successful years.
"So [like] a 2008 car, with a very wide front tyre, very, very good grip all the way from turn-in up to the apex.
"We've been definitely missing that for the last seven years, and he struggled a little bit with that.
"The more front end you can give Felipe, as long as you have a solid rear, then the more he will be able to deliver from his driving style.
"And from what we have seen at the minute, he's very very comfortable."
Indeed, Massa's relative performance in Formula 1 since his title-challenging season in 2008 hasn't been all that remarkable.
But with confidence and comfort now emerging once again, the Brazilian has the potential to shine.
"I think with Felipe, you always know if you are on to a winner with the amount of mistakes he makes the first time he gets into a new car.
"I think that over the course of however many thousand kilometres he has done over the past few days, he has perhaps run wide twice and has made hardly any mistakes on new tyres. So he is obviously extremely comfortable with the car.
"When we put a different compound on, when we perhaps increase the engine or reduce the fuel level to a lower level, he delivers exactly what you expect him to do.
"It shows that ultimately he is very, very comfortable."