|Chinese Grand Prix|
|Venue: Shanghai International Circuit. Date: 10-12 April|
|Live commentary on BBC Radio 5 live sports extra; text commentary on BBC Sport website; highlights on BBC One|
Lewis Hamilton set an impressive pace for Mercedes in the first practice session at the Chinese Grand Prix.
Hamilton was 0.5secs clear of team-mate Nico Rosberg - and 1.1secs ahead of Ferrari's Sebastian Vettel in third.
The gap from Mercedes to the rest suggests they may be back to their dominant best after the surprise defeat by Vettel last time out in Malaysia.
McLaren-Honda made progress, with Jenson Button 13th fastest and Fernando Alonso as high as seventh early on.
On a day when the sun made it through the perpetual Shanghai smog, but on which temperatures remained much cooler than the oppressive tropical heat of Malaysia, several drivers struggled with a lack of grip.
Among them were Lotus reserve driver Jolyon Palmer, the British GP2 champion spinning at Turn Eight early in the session on his first outing at a grand prix weekend.
Palmer acquitted himself solidly, ending up 15th, 0.6secs slower than team-mate Pastor Maldonado.
Hamilton and Rosberg both also ran off the track, struggling with locking brakes at Turn Six, which caught out several other drivers.
But the Mercedes appeared to be on a separate level from the rest of the field - and Hamilton one step ahead of Rosberg at the same time.
Hamilton failed to record a time during the first half-hour of the session, but his potential was clear as he set fastest times in the first two sectors only to abort his fastest lap with a mistake at the hairpin at the end of the long back straight.
But when he strung a lap together later on, he was 0.541secs ahead of Rosberg.
Vettel was 1.124secs off the pace, and continuing the theme of the season in being only fractionally faster than Raikkonen, who was just 0.107secs adrift of the German.
Sauber's Felipe Nasr was fifth, 0.017secs ahead of the Red Bull of Daniel Ricciardo, who was 0.068secs ahead of team-mate Daniil Kvyat.
For Red Bull, despite a power deficit from the Renault engine compared to Mercedes and Ferrari, it was a much better performance after struggling in Malaysia.
Carlos Sainz Jr, driving for the Red Bull feeder team Toro Rosso, was eighth, ahead of the Williams of Valtteri Bottas and Massa.
McLaren, who have been the slowest team in the first two races this season as new engine partner Honda finds its feet, were for the first time in the mix with the rest.
Fernando Alonso was seventh fastest after the first half-hour of runs but the Spaniard failed to improve his time for the rest of the session.
Button had been nearly 0.276secs off Alonso after the first runs, but ended up 0.316secs ahead after an improvement on his second run as both drivers evaluated aerodynamic changes to the car, with the help of luminous 'flo-vis' paint, with which engineers can see the airflow over parts of the car.
At the back, Will Stevens beat Manor team-mate Roberto Mehri by more than a second but was still 6.346secs off the pace.
|Andrew Benson's Chinese GP view|
|It may have the longest straight and, in Turn One, probably the longest corner on the F1 calendar, but the Shanghai International Circuit is more memorable for the smog that perpetually envelopes it than any of its physical characteristics.|
|It ticks the box of giving F1 a race in China - a requirement that in the modern world no self-respecting 'world' championship could do without - but inspirational it is not.|
|The track's stand-out feature is probably the back end of the paddock, where the vast concrete expanse behind the garages gives way to a series of pavilions dotted around a small lake, which the teams use as their offices for the grand prix weekend.|
|It's a lovely idea, and really quite attractive, but it can turn finding anyone to talk to into something of an odyssey.|
|Still, the place has thrown up some decent races in the past, and there is an element of exoticism about any trip to Shanghai.|