Ferrari driver Felipe Massa says Toyota could be a threat this season following their impressive form in testing.
Asked if he expects the usual teams to be contesting podium places in 2009, the 27-year-old Brazilian said there could be surprise front-runners.
"It may be a bit different this year," he said. "I see Toyota in good shape."
Massa also said other teams may be wary of former Honda team Brawn GP ahead of the Sunday's richly-anticipated season opener in Melbourne.
"They [have] surprised everybody," he told BBC Sport.
"Ross Brawn is a very good engineer. We need to wait and see but definitely they have surprised everybody."
This is a big season for our team and we have set ourselves high targets
Toyota F1 president John Howett
Despite being a well-funded team backed by a big manufacturer, Toyota have not yet won a Grand Prix since joining the grid in 2002 - but the Japanese team is eyeing 2009 as its breakthrough season.
Drivers Jarno Trulli and reigning GP2 champion Timo Glock have both gone well in testing - most notably Glock's best time of 1:20.091 seconds over the course of 128 laps in Barcelona - ahead of a race calendar in which no in-season testing will take place.
"This is a big season for our team and we have set ourselves high targets," said Toyota Motorsport president John Howett.
"We exist to win so that is clearly the aim this season and we have every reason to be optimistic after our extremely positive testing results.
Toyota's Glock is considered to have a lot of potential as an F1 driver
"This is our eighth season in Formula One and we have learnt a lot in that time; we are leaner, more experienced and better equipped to succeed."
Italy's Trulli, who made his F1 debut for Minardi in Australia in 1997, echoed those views.
"I am totally fired up for this season and I am feeling very positive about our chances," he said.
"The TF109 is the best Toyota I have driven in pre-season testing. It feels stable and gives the driver confidence but more importantly it seems to be pretty quick, even though it's hard to make too many judgements based on testing."
Germany's Glock added: "It's very exciting to be going to the first race this year because the big changes to the technical regulations for 2009 give Toyota a good opportunity to fight at the front."
Massa, who finished just one point eventual 2008 world driver's championship winner Lewis Hamilton, also lauded the efforts of BMW - and said his Ferrari team would face a serious challenge as one of the strongest teams.
"Everybody in F1 knows how to win and if they have a competitive car most of the drivers can fight for the championship, and that's why we need to be very careful and prepared for everything," he said.
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