As Hamilton bested Rosberg by three-tenths of a second, with Bottas another three-tenths back, Ricciardo ended up 13th after losing control at Turn 15 with just over 20 minutes to go, ripping the right-rear off his RB12 and leaving his Red Bull mechanics with a lot of work to do ahead of FP2.
After all their talk of struggling on Baku’s long straight, McLaren finished the session fourth courtesy of Fernando Alonso, albeit over 1.5s off Hamilton’s pace, with the Spaniard separated from team mate Jenson Button in the times by Ferrari's Sebastian Vettel and Force India’s Sergio Perez.
Felipe Massa was eighth for Williams, with the top ten completed by Toro Rosso's Carlos Sainz and Force India's Nico Hulkenberg.
Esteban Gutierrez took the accolade of being the first man to drive an F1 car here in the Haas, but it was Rosberg who recorded the first timed lap, a tentative 1m 57.306s on the soft-compound Pirelli tyres. He improved that to 1m 53.481s next time around.
The German then worked down to 1m 50.100s before Hamilton redefined the ante with 1m 49.174s. Subsequently, the world champion reduced his time to 1m 48.214s to Rosberg’s 1m 48.473s after their first round of runs, with Bottas a promising third for Williams on 1m 49.923s.
Just on the hour mark, when the Mercedes were in the pits, the Finn went fastest, half a second quicker, with 1m 47.707s on the softs. Soon afterwards, he complained of wisps of smoke in the cockpit.
At the halfway point Mercedes switched to supersoft tyres, with Toro Rosso the only other team to do so.
Rosberg went fastest with 1m 46.812s before complaining of something in the back of the seat digging into him, then Hamilton beat his time with 1m 46.489s. He then improved that to 1m 46.435s, before running off slightly at Turn 3 after kissing the wall on entry. Next time around he did the same at Turn 1, and then again at Turn 3. He pitted, and his session was over.
Soon after Bottas had improved his soft-tyre time to 1m 47.096s, the session was red flagged when Ricciardo made a rare mistake at Turn 15. The Australian became the first man seriously to damage a car here when he smashed his Red Bull’s right-rear suspension into the wall. With Max Verstappen troubled by an oil leak, it was a trying first session for the team.
When the track went green again Carlos Sainz also got into trouble approaching 15, but after electing not to use the escape road he just got his Toro Rosso stopped and nudged his front wing against the outer wall, causing some damage.
On a good morning for McLaren, Alonso was fourth on 1m 47.989s as Vettel posted 1m 48.627s literally as the flag fell. Perez was sixth on 1m 48.922s for Force India, ahead of Button on 1m 49.019s. Massa with 1m 49.125s, Sainz on 1m 49.267s and Hulkenberg on 1m 49.30s completed the top 10.
Naturally such a new track surface was slippery and ‘green’, and Vettel was the first man to go off, spinning at Turn 16 early on, while Gutierrez went off at Turn 15 and had to do a multi-point turn to get out, and later at Turn 4. Sauber’s Marcus Ericsson went off at Turn 1, while Renault’s Kevin Magnussen and Button both joined Hamilton in trying out the run-off at Turn 3, which had been increased.
The award for best recovery went to Daniil Kvyat, who went off there and executed a perfect spin-turn in his Toro Rosso to get back out very quickly and efficiently.