Sebastian Vettel set the pace on the opening morning of pre-season testing as the F1 teams debuted their 2016 challengers.
It was a damp and chilling start to the morning at the Circuit de Barcelona-Catalunya as many of the teams took the covers off their new cars.
Lewis Hamilton in his W07 was the first driver out on track followed by Renault's Jolyon Palmer, Valtteri Bottas in the Williams and Red Bull's Daniel Ricciardo.
It was the latter who set the first lap time of the pre-season as he crossed the line with a 1:40.746.
That was soon topped by Hamilton, who briefly lost the P1 to other challenges only to respond by upping his pace.
However 20 minutes before lunch Vettel hit the front with a 1:24.939, edging the World Champ by 0.470s.
The Mercedes driver topped the list for the most laps completed as he covered 66 on Monday morning.
Second in line was Bottas as the Williams driver managed 43. He was also third quickest on the timesheet, 1.152s off the pace.
There was only one red flag on Monday morning which belonged to Romain Grosjean.
The new Haas driver lost his front wing down the main straight, causing debris that the marshals had to sweep clear before the session could be restarted.
1 Vettel Ferrari 1:24.939 36 laps
2 Hamilton Mercedes 1:25.409 66 laps
3 Bottas Williams 1:26.091 43 laps
4 Ricciardo Red Bull 1:26.704 20 laps
5 Sainz Toro Rosso 1:27.180 35 laps
6 Button McLaren 1:27.691 35 laps
7 Ericsson Sauber 1:28.165 36 laps
8 Grosjean Haas 1:28.399 13 laps
9 Celis Force India 1:29.406 21 laps
10 Palmer Renault 1:31.351 15 laps
11 Wehrlein Manor 1:33.455 8 laps