Reigning Formula 1 champion Lewis Hamilton clocked a time of 1:46.435 to end the first practice session of the European Grand Prix fastest in Baku.
Hamilton's Mercedes teammate Nico Rosberg was second quickest, while Valtteri Bottas grabbed the third-fastest time in his Williams on the circuit.
There have been safety concerns in the run-up to the maiden race in Baku as there is a lack of run-off areas at Turns Three, Seven and 15.
It proved to be an issue during practice as Hamilton caught his wheels on Turn Three twice, while Daniel Ricciardo smashed his Red Bull into the wall at Turn 15, resulting in his rear right wheel coming loose.
Ricciardo's teammate Max Verstappen encountered problems with his car when a leak was spotted, but the 18-year-old was relaxed about the issue after returning to the pits.
Sebastian Vettel made a late surge in his Ferrari to clock the fifth-fastest time behind McLaren's Fernando Alonso.
First practice session:
1. Lewis Hamilton (Mercedes)
2. Nico Rosberg (Mercedes)
3. Valtteri Bottas (Williams)
4. Fernando Alonso (McLaren)
5. Sebastian Vettel (Ferrari)
6. Sergio Perez (Force India)
7. Jenson Button (McLaren)
8. Felipe Massa (Williams)
9. Carlos Sainz Jr (Toro Rosso)
10. Nico Hulkenberg (Force India)
11. Romain Grosjean (Haas)
12. Kimi Raikkonen (Ferrari)
13. Daniel Ricciardo (Red Bull)
14. Esteban Gutierrez (Haas)
15. Marcus Ericsson (Sauber)
16. Max Verstappen (Red Bull)
17. Daniil Kyvat (Toro Rosso)
18. Jolyon Palmer (Renault)
19. Kevin Magnussen (Renault)
20. Pascal Wehrlein (Manor)
21. Felipe Nasr (Sauber)
22. Rio Haryanto (Manor)
