Ландо:
McLaren 2019 hopeful Lando Norris made his grand prix weekend debut with the team, driving in place of the outgoing Fernando Alonso in FP1.
He set the 18th-fastest time, 3.006s off the pace, but was just under a tenth quicker than team-mate Stoffel Vandoorne, who brought up the rear of the field.
Norris and Vandoorne are vying for the second McLaren seat alongside Sainz for next season, with Ocon also a contender.
Vandoorne, who moved to quash speculation suggesting he could lose his McLaren drive as early as next weekend in Italy, was hampered by a brake problem early in the session.
He then lost more track time at the end of the session as the team removed the floor to investigate a suspected leak.
FP1 resultsPos Driver Car Gap Laps
1 Sebastian Vettel Ferrari 1m44.358s 19
2 Max Verstappen Red Bull/Renault 0.151s 20
3 Lewis Hamilton Mercedes 0.318s 22
4 Kimi Raikkonen Ferrari 0.360s 17
5 Valtteri Bottas Mercedes 0.366s 25
6 Daniel Ricciardo Red Bull/Renault 1.200s 4
7 Esteban Ocon Force India/Mercedes 1.428s 22
8 Nico Hulkenberg Renault 1.593s 19
9 Sergio Perez Force India/Mercedes 1.811s 21
10 Carlos Sainz Renault 1.852s 19
11 Pierre Gasly Toro Rosso/Honda 1.942s 25
12 Romain Grosjean Haas/Ferrari 2.029s 20
13 Charles Leclerc Sauber/Ferrari 2.196s 20
14 Marcus Ericsson Sauber/Ferrari 2.199s 19
15 Brendon Hartley Toro Rosso/Honda 2.574s 23
16 Lance Stroll Williams/Mercedes 2.607s 25
17 Kevin Magnussen Haas/Ferrari 2.654s 21
18 Lando Norris McLaren/Renault 3.006s 2619 Sergey Sirotkin Williams/Mercedes 3.009s 23
20 Stoffel Vandoorne McLaren/Renault 3.094s 13