Ferrari junior Antonio Giovianzzi led the field in the first part of day 1 of Formula 1's in-season test at the Hungaroring.
The young Italian, who will switch over to Sauber on Wednesday, clocked in with a best time of 1m19.648s achieved on Pirelli's soft compound tyres after completing 66 laps.
It was a smooth morning session overall with no drama to report. Lando Norris, who is McLaren's exclusive driver for the two-day test, was second, 0.318s behind Giovinazzi while Force India's Nicholas Latifi was third, 0.028s behind Norris.
Force India, Williams and Red Bull all trialed a 2019-spec front wing early on in the session.
Teams will resume their running at 14h00 local time.
1. Antonio Giovinazzi, Ferrari, 66 laps, 1:19.648
2. Lando Norris, McLaren, 46 laps, 1:19.966
3. Nicholas Latifi, Force India, 66 laps, 1:19.994
4. Marcus Ericsson, Sauber, 63 laps, 1:20.081
5. Brendon Hartley, Toro Rosso, 94 laps, 1:20.151
6. George Russell, Mercedes, 21 laps, 1:20.231
7. Daniel Ricciardo, Red Bull, 76 laps, 1:20.304
8. Nico Hulkenberg, Renault, 63 laps, 1:20.826
9. Oliver Rowland, Williams, 43 laps, 1:21.594
10. Sean Gelael, Toro Rosso, 68 laps, 1:21.861