Massa and Bottas admit Williams has become F1's third-best team

The Chinese Grand Prix was the second consecutive race in which the two Williams finished behind a quartet of Mercedes and Ferraris in distant fifth and sixth places.

Although Massa and Bottas ran comfortably clear of Romain Grosjean's Lotus in seventh before the safety car came out, they were more than 40 seconds adrift of race winner Lewis Hamilton's Mercedes.

"To be honest, we finished where we are for the moment," said Massa. "We are the third team for the moment, we finished fifth and sixth.

"Definitely it would be nice to finish in front of Ferrari but also closer to Mercedes as we're always looking forward, but it's not the case."

Bottas added: "It looks now quite clearly that we are the third-quickest team.

"We have a good margin from the rear so we just need to try to do anything we can to move forward."

Massa said Williams's advantage over the teams behind at least gave it a comfort zone while trying to get back on terms with Mercedes and Ferrari - having been clearly ahead of the Italian team and sometimes challenging the champion squad in 2014.

"We need to push to improve but we can say it is also not so negative because we are third in the championship and we are building good points compared to the guys behind which is positive," he insisted.

"We need to work, we need to make the car better to catch these guys in front, which is not easy."