What were the outcome of Day 1 testing?

Day 1 of testing was eventful. All the teams did their tests according to the plan. Verstappen was the only one to drive and test the car for the whole day. He did the most laps 157. Red bull seemed to do their tests according to the plan. Red bull was the only one that did their programs without any problems.

Red Bull

Red bull was the only team to be more consistent with the mileage. That means their engine is reliable and according to Helmut Marko, there is an increase in the power of the Honda engine. Verstappen was the quickest with Alonso just sitting behind with a 0.029 difference in second place. The red bull seemed to have no problems at all. 

Ferrari

Ferrari ran its two sessions with Carlos Sainz and Charles Leclerc. Ferrari seemed to have no problems with the mileage. Charles Leclerc sacrificed most of his time to discover the best possible setup to race with. Charles Leclerc was mostly focused on long runs and Carlos Sainz initially put in some quick laps but was also focused on long runs.

Mercedes

Mercedes ran the car all day with no problems. According to Toto Wolff Mercedes has a more improved package than last year. Mercedes didn't seem to bounce at all. Mercedes has a very good and stable base to evolve with. Mercedes can start their aggressive development by collecting some data. Lewis Hamilton was quick during the long runs and during a fast lap. Mercedes looked to be the most stable car when riding onboard with the two drivers.

Aston Martin

Aston Martin initially had some issues with Felipe. The issue was in the steering wheel not to be concerned. Afterward, both Felipe and Alonso put in some quick laps that encouraged the technicians. 

Alonso was second fastest behind Verstappen by the slimmest of the margins. Aston Martin looked like a more stable car and Alonso also beat the Qualifying lap of Stroll.