BERLIN, Germany - Mercedes motorsport chief Toto Wolff has played down expectations for the 2013 Formula 1 season after the team's top test times in pre-season testing in Barcelona.Wolff said: "I have to dampen them because they are quite simply not realistic. It is, of course, pleasant to be at the front in testing but it means nothing."Nico Rosberg posted the fastest time in (northern) winter testing at the Circuit de Catalunya the day after team mate Lewis Hamilton set the pace in the Mercedes W04. All that has led to hopes that, after a disappointing 2012, Mercedes could be a real challenger when the 2013 F1 title race is flagged away on March 17 with the Australian GP in Melbourne.'THE TRUTH IS...'However Wolff, who has replaced Norbert Haug as motorsport chief, said it would be wrong to draw any conclusions from the tests. "It is perhaps a cliche but test drives and races are two different things. We are there to race."I don't think you can interpret too much into the test results. It was incredibly cold here and the teams drove with different fuel loads. You could theoretically deduce if a car is right or not but the truth is that you can't see anything. (World champion) Red Bull, for example, showed nothing. We won't know until Melbourne what's really going on."He added that Mercedes followed its test programme without worrying about what other teams were doing."We worked out our plan and drove what we wanted, but not to impress anyone or to bluff." Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.