Nico Rosberg insists Mercedes are not "ahead of the game" despite racking up more than 100 laps on the opening day of testing in Spain.
After dominating the 2014 season with 16 grands prix wins from 19 races, Mercedes are once again expected to be the pacesetters this season and Rosberg certainly showed the abilities of the new W06.
Although Sebastian Vettel of Ferrari topped the timesheets with a 1:22.620, Rosberg was only 0.486s off his German compatriot's pace and also completed 157 laps – 84 laps more than the next best.
However, the Mercedes driver warns it is way too early to draw conclusions, especially with several test days still ahead.
"We have Red Bull, for example, who just one year ago were the untouchable team, so you can expect them to very strong," he said.
"Then you have Ferrari, then you have McLaren with Honda, then there's Williams who were right on our tail at the end of the season, they finished the season three seconds away from us and Lewis was pushing. In many ways we definitely expect our competitors to close the gap and we have a close eye on them and we hope we have done enough over the winter and made enough progress to stay ahead."
He added on Crash.net: "Ahead of the game, no, but we got off to a good start for ourselves. We're not comparing with anybody else because it's not possible to compare at the moment. We can only judge by what we wanted to achieve today and we managed to achieve that – the laps we wanted to do, the pit-stop practice at the end. For us, that was a good start."