Former Austrian Formula One World Champion Niki Lauda talks to journalists in the paddock prior to the British F1 Grand Prix at Silverstone, central England July 9, 2011. REUTERS/Leonhard Foeger (BRITAIN - Tags: SPORT MOTOR RACING)

Berlin, Germany - Formula One legend Niki Lauda says Mercedes should not get carried away with its success in testing before the 2014 Formula One season.

“There is no comparison to actual racing, “ he told the online edition of Auto, Moto and Sport magazine on Friday.

“Everything is theory because you don't know who has already played out how much of their resources.”

“The truth will be only be seen in Australia.”

“Every time it comes down to the aerodynamics and the engine, “ added the three-times world champion.

The efforts of Mercedes drivers Nico Rosberg and Lewis Hamilton have been particularly impressive so far when compared to current world champion Red Bull which has struggled with car and engine problems. The third and final pre-season test continued at the Sakhir track in Bahrain, ahead of the season opening Australian Grand Prix in Melbourne on 16 March.