A big crash involving Carlos Sainz brought a red flag and early end to free practice at the Russian Grand Prix in Sochi on Saturday.

The Toro Rosso driver - who was later pictured giving a thumbs-up gesture on his way to the medical centre - came off the track at turn 13 in the final session ahead of qualifying for the grand prix on Sunday, colliding heavily with the barriers with 22 minutes remaining.

With little time between FP3 and qualifying the session was immediately red flagged to remove Sainz and his car from the barriers, with race control confirming the rest of the paddock would not return to the track while they attended to the Spaniard.

Sainz's accident brought an end to the best practice of the weekend after a diesel spillage in FP1 and heavy rain in FP2 on Friday.

As the 60-minute session ended it left championship contender Nico Rosberg top of the timesheets in his Mercedes with a time of one minute 38.561 seconds.

The German held a 0.726secs advantage over Williams' Valtteri Bottas, with Lewis Hamilton trailing his Mercedes team-mate by 0.802secs.

Meanwhile, there was some positive news for McLaren, with both Jenson Button and Fernando Alonso inside the top 10 times heading into qualifying.

1.            Nico Rosberg (Mercedes) 1:38.561s
2.            Valtteri Bottas (Williams) 1:39.287s
3.            Lewis Hamilton (Mercedes) 1:39.363s
4.            Sergio Perez (Force India) 1:39.616s
5.            Felipe Massa (Williams) 1:39.875s
6.            Nico Hulkenberg (Force India) 1:39.917s
7.            Jenson Button (McLaren) 1:40.581s
8.            Pastor Maldonado (Lotus) 1:40.767s
9.            Fernando Alonso (McLaren) 1:41.200s
10.          Felipe Nasr (Sauber) 1:41.229s