(GMM) Mercedes is emerging as a surprise contender to take on world champions Red Bull in 2013.
With McLaren and Ferrari perhaps slightly off the ultimate pace in winter testing, most pundits were looking to Lotus to take the fight to Red Bull this year.
But Jenson Button said in Barcelona on Friday: "The one team that has been consistently quick has been Mercedes more than anyone else."
Michael Schmidt, the respected correspondent for Germany's Auto Motor und Sport, agrees that the silver-clad team has "stunned the competition" with its pace at the final Barcelona test this week.
Meanwhile, Mercedes is one of the teams that has been experimenting with the allowed 'passive double DRS' concept in recent testing.
The system, attached to the rear wing, has not been difficult to spot at times on the cars fielded in Barcelona by Lotus, Mercedes, Sauber and Red Bull.
Red Bull was fitted with the wing-stalling device all day on Friday.
"Until now, the systems were always being tried only briefly," said Mercedes' Aldo Costa.
"But whoever wants to use it in Melbourne needs to use it at least during one day of testing."
Sauber designer Matt Morris said the innovation is worth between "a few hundredths to a tenth" of a second per lap.
"And a tenth can make a huge difference when the cars are so closely matched," he added.
Lotus' Kimi Raikkonen sat out Saturday's penultimate day of winter testing with food poisoning. Reserve driver and reigning GP2 champion Davide Valsecchi is standing in for the Finn.