Sebastian Vettel set the fastest time on the opening day of pre-season testing, while Mercedes completed impressive mileage.
With the Ferrari having been top of the times at the lunch break, Vettel's best lap of a 1:24.939 went unbeaten in the afternoon session as he ended the opening day fastest for the second year in a row. Vettel only added 33 laps to his tally after lunch, while Lewis Hamilton in the Mercedes displayed strong reliability throughout the day.
Hamilton was second fastest having also failed to improve on his morning time - leaving him 0.470s adrift of Vettel - but completed a mammoth 156 laps across the day. The reigning champion's total was more than two race distances and saw Mercedes exceed the amount of kilometres it completed on the opening day of 2015.
Daniel Ricciardo was third quickest on an encouraging day for Red Bull, with the new RB12 also running reliably. Ricciardo was 1.1s slower than Vettel and a little over 0.6s off Hamilton, but the 87 laps completed will represent a good start for a Red Bull team which has struggled during pre-season for the last two years.
Ricciardo only just edged out Valtteri Bottas in terms of best lap times, with the Williams not improving in the afternoon session. Bottas completed 80 laps in the FW38 which the team hopes will be a stronger all-round package having struggled in low-speed corners last season.
Force India development driver Alfonso Celis was fifth in the new VJM09, though the team did struggle slightly for track time as he completed just 58 laps.
One team to show a major step forward compared to a year ago was McLaren, with Jenson Button getting its pre-season off to a promising start. Button was able to complete 84 laps on the opening day, five laps more than McLaren managed in the whole of the first test last year. On top of the important reliability, Button was also less than 1.8s off Vettel's best time.
The Toro Rosso STR11 was seen for the first time when Carlos Sainz took to the track on Monday, though the car is running in a blue testing livery. Sainz was nearly half a second slower than Button and a gearbox oil system problem meant he only managed 20 laps in the afternoon session after a solid morning's running.
Sauber completed solid mileage using its 2015 car, with Marcus Ericsson's total of 88 laps being the second highest behind Hamilton.
While many teams are running similar cars to last season, the new Manor broke cover on Monday morning and made a strong start to the year as Pascal Wehrlein completed 54 laps. Mileage was hard to come by in the morning but the afternoon session was much more productive and saw Wehrlein set a best time 3.3s slower than Vettel.
New team Haas had a slightly bittersweet day as a front wing failure for Romain Grosjean before lunch caused the only red flag of the day. Grosjean was confined to the garage for a large portion of the day as the team investigated the issue, but managed to the track return late on to bring his lap total up to 31 and end the day just 0.1s behind Wehrlein.
Renault was up against it to get its car ready for the start of running - launching 40 minutes later than planned - and appeared on the back foot for most of the day as a result. Jolyon Palmer managed just 37 laps - with only Grosjean completing fewer - and set the slowest time of Monday's running, 4.4s off the Ferrari pace.