Valtteri Bottas led Lewis Hamilton to a Mercedes one-two in second practice at the Abu Dhabi Grand Prix.
Listen to final practice and qualifying on BBC Radio 5 Live Sports Extra and the BBC Sport website from 09:55 GMT on Saturday
Bottas was 0.310 seconds ahead of Hamilton, who was 0.076secs faster than Ferrari's Charles Leclerc as the season's final race weekend began.
In an unusual crash for a practice session, Bottas and Haas' Romain Grosjean collided at a chicane.
The Finn dived for the inside at the end of the second long straight and Grosjean turned in having not seen him.
Both cars suffered extensive damage and showered the circuit with debris, causing the session to be stopped for seven minutes while the track was cleared.
Bottas and Grosjean were called to the stewards after the session, and the Mercedes driver was given a reprimand for his actions.
Until his crash, Bottas was on excellent form around Yas Marina on Friday, fastest in both sessions, but he has a grid penalty for excessive engine usage and will start the race from the back of the grid.