Formula 1:Red Bull's Sebastian Vettel once again demonstrated his supremacy over his Formula One rivals as he posted the quickest time in second practice for Sunday's Chinese Grand Prix in Shanghai.
The reigning world champion was quickest in the morning's first session and maintained his stranglehold with another perfectly judged display, his time of one minute 37.688 seconds enough to eclipse second-placed man Lewis Hamilton by 0.166secs.
It was a low-key session for Vettel's team-mate Mark Webber, however, as the Australian appeared to concentrate on longer runs in the second RB7 to finish down in 10th place, 1.6secs down on the German.
Vettel is aiming to continue his perfect start to the season with another pole position and victory to add to those achieved in Australia and Malaysia. He leads the world championship on 50 points, 24 clear of nearest challenger Jenson Button.
Button was third in the afternoon practice session, just a tenth down on Hamilton as the McLaren team-mates again continued their bid to successfully integrate new floor and exhaust upgrades.
Mercedes, meanwhile, looked in better shape than they had in first practice. Nico Rosberg and Michael Schumacher topped the timesheets with 30 minutes remaining after switching to the softer tyre, but eventually settled for fourth and fifth respectively.
Felipe Massa was sixth for Ferrari, although his team-mate Fernando Alonso battled with hydraulic problems during the session and could only manage 14th from just 17 laps on track.
Adrian Sutil was seventh for Force India, but it was a bad session for his team-mate Paul di Resta, the Scotsman failing to get out for any of the 90-minute session due to a fuel pressure problem.
Renault's Nick Heidfeld was another to suffer, the German, who finished third at Sepang last Sunday, committing his second error of the day when he ran wide at turn two.
Heidfeld knocked loose the front wing of the R31 - as he did after a spin in the opening practice session - but was able to slowly recover to the pit lane entrance where his mechanics wheeled him back to the garage and patched him up.
He recovered to finish in eighth, one place ahead of team-mate Vitaly Petrov.
The midfield saw the regular mash-up of Saubers, Williamses and Toro Rossos, while at the rear it was again the usual suspects.
Lotus pair Heikki Kovalainen and Jarno Trulli were best of last season's new boys, while it was an encouraging session for Hispania, with Narain Karthikeyan and Vitantonio Liuzzi taking 20th and 21st, comfortably ahead Virgin duo Jerome d'Ambrosio and Timo Glock.
Times
01. Sebastian Vettel Red Bull 01:37.688 34 laps
02. Lewis Hamilton McLaren 01:37.854 22 laps
03. Jenson Button McLaren 01:37.935 31 laps
04. Nico Rosberg Mercedes GP 01:37.943 34 laps
05. Michael Schumacher Mercedes GP 01:38.105 29 laps
06. Felipe Massa Ferrari 01:38.507 38 laps
07. Adrian Sutil Force India 01:38.735 35 laps
08. Nick Heidfeld Renault 01:38.805 28 laps
09. Vitaly Petrov Renault 01:38.859 31 laps
10. Mark Webber Red Bull 01:39.327 33 laps
11. Kamui Kobayashi Sauber 01:39.538 33 laps
12. Pastor Maldonado Williams 01:39.867 37 laps
13. Sebastien Buemi Toro Rosso 01:39.771 18 laps
14. Fernando Alonso Ferrari 01:39.779 17 laps
15. Jaime Alguersuari Toro Rosso 01:39.828 25 laps
16. Rubens Barrichello Williams 01:39.925 32 laps
17. Sergio Perez Sauber 01:39.953 30 laps
18. Heikki Kovalainen Team Lotus 01:40.476 30 laps
19. Jarno Trulli Team Lotus 01:41.482 32 laps
20. Narain Karthikeyan HRT F1 Team 01:42.902 25 laps
21. Vitantonio Liuzzi HRT F1 Team 01:43.850 3 laps
22. Jerome d' Ambrosio Virgin Racing 01:44.008 35 laps
23. Timo Glock Virgin Racing 01:44.747 12 laps
24. Paul di Resta Force India no time