Felipe Massa believes Ferrari's extra resources are starting to show in the battle with Williams for a place on the podium.
This year Ferrari made a big step forward over the winter and has emerged as a potential rival for Mercedes. In doing so it has leapfrogged Williams, which has been a threat to Ferrari in qualifying but often dropped off in the race.
Ferrari is among the best funded teams in F1, while Williams is still independent and running as an engine customer to Mercedes rather than a works team. Massa believes the gap between the two in races this year represents the funding behind the two outfits.
"If you have two teams that are working in the right way but one team has also double the budget it makes a difference," he said. "If you have a team that is struggling for different reasons then the money makes less of a difference, but if you have both working in a good way with an understanding then it's good to have the more and more [money] you can. It's clear."
Massa believes Ferrari's main advantage over Williams lies in its use of tyres during the race.
"The only thing that changed [from 2014] was Ferrari compared to everybody else," he added. "In Melbourne we were a little bit slower, we were maybe better in the qualifying, but even in the last qualifying [in China] we were qualifying both cars in the middle of the two Ferraris. We are in the fight in the qualifying, but Ferrari is the only team that makes a big gap between qualifying and the race, so Ferrari took more than a second, maybe a second, compared to Mercedes in the last qualifying compared to the race. One second, I tell you, is a lot of time.
"I think Ferrari is maybe the team that has the tyre usage in a completely different way to everybody, and for sure we are working to get as close as we can, but they use the tyres in a completely different way and they have a lot less degradation than everybody - even compared to Mercedes, because if you take one second in the qualifying and you are in the same pace in the race, even compared to Mercedes they are better. I think they are the only team that makes that gap from qualifying to the race and for us it was not easy to have the same pace because we couldn't, until now, use the tyres in the same way."
Massa believes Ferrari will be strong this weekend as the conditions and demands of the track are closest to Malaysia.
"In Malaysia everything was related to the rear tyres and they won the race, so here is another track where the rears are a lot more important than the front, in China it was a lot related to the front tyres and they [Ferrari] still had a good pace. I think they proved in a different type of track that they were strong in the race, so I think we cannot stop working and stop understanding the car and trying to improve. But it's also true that we are third in the championship as well, so it's not that we are having a complete disaster at the beginning of the season, it's not correct to say that, we just need to see if we can fight with the Ferrari because Mercedes is already far, but anyway Ferrari is not far from Mercedes."