Felipe Massa is convinced Williams can push Mercedes all the way when Formula One returns from its summer break.

Williams have been a revelation this year, scoring almost as many points in the first 11 races as they have managed in the previous four years following the introduction of the new scoring system.

Unfortunately for Massa, in his first year with the team after many seasons of service with Ferrari, the Brazilian has been plagued by bad luck and involved in a number of incidents.

It means Massa has scored only 40 of Williams' 135 points in total, compared to the 95 for team-mate Valtteri Bottas.

But the 33-year-old has no doubt he and Williams can deliver over the final eight races, in particular in the opening two in Belgium and Italy where the power circuits of Spa and Monza should play to the car's strengths.

"I'm sure we can have a very good second half of the season looking at the behaviour of the car until now," said Massa. "Spa and Monza should suit us, maybe Austin and Brazil, and in the last race in Abu Dhabi there are some good straights.

"The car can be competitive at many tracks, not just Spa and Monza, but maybe at those two we can be stronger than the others.

"It won't be easy, but it's not impossible that at these tracks we will have more of a chance against Mercedes."

After a number of tough years for the Grove-based marque, Massa has conceded no-one within the team was expecting this year to be so good.

"Everybody has been surprised at the competitiveness of the car," added Massa. "I obviously expected to have a much better car than the team had in the past, this was clear, but it was too much to think about doing so well in the championship.

"What we have done from the winter through to now has been a very good job from everybody on the technical side.

"There is still a lot we can do, but everything is progressing in a good way in terms of development, and I hope we can do even more from now until the end of the season."

Following Sunday's Hungarian Grand Prix, even though Massa and Bottas were fifth and eighth respectively, Williams slipped from third to fourth in the constructors' championship.

Although 84 points adrift of second-placed Red Bull, Massa feels it is not beyond the realms of possibility Williams could finish the season as runner-up to Mercedes.

Massa said: "Anything is possible, when you look at the maths and there is this possibility, why not? We need to fight for that.

"We need to try to do everything. If we do a perfect job from now until the last race then it can be possible."