Qualifying is live on BBC Radio 5 Live Sports Extra and the BBC Sport website from 14:00 BST
Charles Leclerc led a Ferrari one-two in an incident-packed second practice at the Azerbaijan Grand Prix.
The 21-year-old led the way for much of the session and ended it 0.324 seconds ahead of nominal team leader Sebastian Vettel with Lewis Hamilton third.
Hamilton was 0.669secs off Leclerc's pace as Ferrari made a flying start to the weekend with an upgraded car.
There were two red-flag periods after crashes for Lance Stroll and Daniil Kvyat.
Stroll lost control of his Racing Point at Turn Two early in the session, taking off his front-left corner after losing the rear on the way into the corner.
And Kvyat had a big impact at Turn Seven with about 25 minutes to go, again because of a rear-end snap, heavily damaging the left-hand side of his Toro Rosso.
Kvyat's crash brought to an end what had been until then a promising session for the Russian. He had a late start to the session as the team fixed a problem on his car, but he had just beaten team-mate Alexander Albon by 0.039secs to go sixth quickest when he braked too late trying to go for a faster time and smashed the car into the wall.
Safety concernsRussell will be unable to take part in third practice on Saturday as his Williams requires a change of chassis
The two incidents cost the teams more time, after the first session was cancelled because George Russell's Williams hit a manhole cover, destroying his car.
In farcical scenes, the truck bringing Russell's car back to the pits crashed into a bridge over the track.
That leaked hydraulic fluid on to Russell's car beneath.
Only the two Ferraris had set lap times when Russell's incident happened, and the session was ended so officials could repair the cover and check the more than 300 around the rest of the track.
In the Formula 2 support race qualifying session that followed two marshals were run over by the rear wheels of a stricken car.
And the stewards may be busy after the second session following two scary-looking incidents.
In one, Red Bull's Pierre Gasly went straight on at Turn Three despite there being waved yellow flags there because Romain Grosjean's Haas had already gone off. Waved yellows means a driver has to slow down and be prepared to stop.
A few minutes later, Hamilton had a contretemps with Grosjean's team-mate Kevin Magnussen on the fast run towards Turn 15, the Dane swerving towards the Mercedes at high speed and then gesticulating at the world champion.
The manhole incident happened between Turns Two and ThreeFerrari look fast
Leclerc's pace threw down the gauntlet to his rivals on a weekend that has started with him making it clear that he intends to force a re-think from Ferrari on their policy of favouring Vettel with team orders this season.
Leclerc was immediately quick at the start of the session, his time on the middle-compound 'medium' tyres 0.7 seconds quicker than Hamilton despite brushing the wall out of Turn Seven, and more than a second up on Vettel.
On the fastest 'soft' tyres, Leclerc went fastest on his first run, nearly 0.7secs quicker than Vettel, before the German responded to sneak ahead, and then Leclerc reclaimed top spot with his third lap.
The Ferraris, fitted with a major aerodynamic upgrade, appeared to have an edge over Mercedes, with Hamilton ending up 0.669secs behind Leclerc.
Red Bull's Max Verstappen was fourth fastest, 0.921secs behind Leclerc, ahead of Hamilton's team-mate Valtteri Bottas and Kvyat.
