Sebastian Vettel played down the significance of topping the timesheets on his Ferrari debut as Formula One testing got underway in Jerez on Sunday.
The four-time world champion moved to the Italian constructor following a disappointing 2014 campaign with Red Bull and immediately showed why Ferrari were so keen to land him.
Vettel completed 60 laps in total at the Spanish circuit and posted the quickest time of the day with a lap of one minute 22.620 seconds.
The German was happy with his progress, but believes there is much to do to match last season's dominant constructor Mercedes.
"Of course it's nice, as the top spot of a timesheet is always nice," he told F1's official website.
"But lap times at tests - especially the first test - have very little significance. It's more for the good feeling.
"We know that we still have a lot to do, as the reference is still Mercedes - and they did something over 150 laps, which means that they start the season with a very reliable car.
"Hopefully they are not as quick as last year. [The aim is] to close the gap to the front-runner. Mercedes did a great job last season that left all others looking a bit pale - so yes, the priority is to get close the gap."
Vettel, who has also driven for Sauber and Toro Rosso, stated that his backroom team at Ferrari have helped him make a seamless transition after six seasons at Red Bull.
"Every team has its own culture - that was so with Toro Rosso and Red Bull and it is also true with Ferrari," he added.
"Probably Ferrari is more a bit like Toro Rosso - also an Italian based team. I had a great time at Red Bull, but to sum it up Ferrari is something special.
"They've made it very easy for me to blend in - they've welcomed me with open arms."