Ferrari driver Sebastian Vettel has said that Mercedes are still clear favourites to triumph in the 2015 Formula 1 season, despite posting the second fastest time in the final day of testing.
The German completed 129 laps of the Circuit de Catalunya but feels that his new team still need to improve to match Mercedes.
"The positive thing is that, once again, we have done a lot of kilometres and gathered useful information," Vettel told reporters.
"The fact that our race simulation went more or less as planned is encouraging from a reliability point of view, although this is an aspect where we can still improve.
"From a performance point of view, it's clear that Mercedes is still ahead by quite a way, but right behind there is us, Williams and Red Bull, all very close. We will know more in a couple of weeks."
Vettel won the Formula 1 World Championship four years in a row between 2010 and 2013.