Reigning World Champion Lewis Hamilton set the pace as teams enjoyed relatively normal conditions to bring the opening pre-season test to a conclusion in Spain.
Unseasonably cold and snowy/wet conditions compromised running across the opening three days, with ntermediate and Wet tyres required for the bulk of the morning while the track surface dried.
Slicks were able to be used shortly before the halfway mark of the session – with the lunch break cancelled in order to make up for lost time – as the benchmark rapidly changed with each lap.
McLaren’s Stoffel Vandoorne used Hypersoft tyres to surge clear, before he was eventually eclipsed by Hamilton, who took over the reins of the W09 from Valtteri Bottas for the afternoon session.
However, Hamilton’s time was deleted for cutting the chicane, before he deposed Vandoorne once more, registering a 1:19.333 on the Medium tyres.
Vandoorne was the only other driver in the 1:19s, finishing 0.521s behind Hamilton, while Sebastian Vettel used Softs to place third, 0.908s down on his Mercedes rival.
Haas’ Kevin Magnussen was fourth, his quickest effort coming on Supersofts, the same compound used by Fernando Alonso to place fifth.
McLaren allocated the final few hours of running to Alonso, as the team finished the day with the most mileage, completing 161 laps.
Renault split running between Carlos Sainz Jr. and Nico Hulkenberg, the pair placing sixth and 11th respectively, while Lance Stroll was seventh, as he tested the FW41 during the afternoon.
Force India’s Sergio Perez finally got his first taste of the VJM11, surviving a trip through the Turn 5 gravel to place eighth, while Red Bull had another frustrating day.
Red Bull opted not to run in wet conditions in the morning and encountered teething issues after lunch, before Verstappen ended the day in the Turn 12 gravel, with only 35 laps to his name.
Toro Rosso-Honda, meanwhile, capped a productive test day with Pierre Gasly completing a mammoth 147 laps, more than any other driver, as he rounded out the top 10.
Bottas finished 12th, in front of Sauber pair Charles Leclerc and Marcus Ericsson, the Swede causing a brief red flag early on when he spun into the Turn 2 gravel, though the off caused little disruption to his programme.
Sergey Sirotkin ran only in wet conditions, prior to Stroll’s stint in the car, explaining his 12s deficit to Hamilton, and eight-second gap to nearest rival Ericsson.
The second pre-season test will take place at the same venue next Tuesday through Friday, when warm and sunny conditions are expected.
| Pos | Driver | Team | Time | Gap | Tyre | Laps |
| 1 | Lewis Hamilton | Mercedes | 1:19.333 |  | 69 | |
| 2 | Stoffel Vandoorne | McLaren | 1:19.854 | 0.521 |  | 110 |
| 3 | Sebastian Vettel | Ferrari | 1:20.241 | 0.908 |  | 120 |
| 4 | Kevin Magnussen | Haas | 1:20.317 | 0.984 |  | 96 |
| 5 | Fernando Alonso | McLaren | 1:20.929 | 1.596 | | 51 |
| 6 | Carlos Sainz | Renault | 1:20.940 | 1.607 | | 60 |
| 7 | Lance Stroll | Williams | 1:21.142 | 1.809 | | 54 |
| 8 | Sergio Perez | Force India | 1:21.973 | 2.640 | | 65 |
| 9 | Max Verstappen | Red Bull | 1:22.058 | 2.725 | | 35 |
| 10 | Pierre Gasly | Toro Rosso | 1:22.134 | 2.801 | | 147 |
| 11 | Nico Hulkenberg | Renault | 1:22.507 | 3.174 | | 49 |
| 12 | Valtteri Bottas | Mercedes | 1:22.789 | 3.456 | | 60 |
| 13 | Charles Leclerc | Sauber | 1:22.808 | 3.475 | | 59 |
| 14 | Marcus Ericsson | Sauber | 1:23.825 | 4.492 | | 79 |
| 15 | Sergey Sirotkin | Williams | 1:31.979 | 12.646 |  | 47 |
