Felipe Massa has played down Williams' performance on the opening day of the Australian Grand Prix, but definitely includes his new employer amongst the contenders for Sunday's opening F1 round.

The Brazilian ended the two practice sessions in twelfth position on the timesheets, four places behind team-mate Valtteri Bottas, but both had posted top five times earlier in the session and only dropped away after switching their attention to longer, race simulation, runs.

"I was just trying to understand everything around the set-up and trying to find the direction for tomorrow," he said of his programme, "That was our focus for today and there is definitely a lot more to come.

"I think [what we learned in testing] puts us in a good position regarding set-up.... I hope so anyway. It's the first day and there is still a lot to happen over the weekend, but it wasn't really a bad day.

As usual, the opening day of the grand prix provided little in definitive information for observers, with each team following its own programme - often amongst dealing with reliability problems still being thrown up by the new technical regulations - and Massa is confident that Williams, buoyed by strong pre-season testing form, can be in the mix through qualifying and the race.

"We have to believe that we have the momentum for a strong result," he said, before identifying the most likely rivals, "I think it is no surprise to see Mercedes there [at the top of the times] and Ferrari was quite strong. I think McLaren maybe will be there, and Red Bull were maybe faster than in testing, but it is too early to be sure about anything. We must see..."

With the Williams pair's times on the harder medium tyre quickly obscured by others switching to the softer option, Massa admitted that there was a big difference between the two compounds.

"We saw the soft was much, much quicker than the medium, not just on the first lap but all the way through the run," he confirmed, "There is a lot to understand still, [but] I think the tyres will make a big difference to the weekend - it will be a big improvement when you go to the soft."