Ferrari finished the Friday practice session in first and third places with Felipe Massa setting the fastest time and team mate Alonso third.
The pair were split by the Lotus of Kimi Raikkonen, with Nico Rosberg fourth ahead of Mark Webber.
It looks like it could be a competitive race, with qualifying certain to be important, but race strategy likely to be the decisive factor, with managing the difference between the soft and medium tyre the key to it.
Mercedes had been the clear pace setters on the medium tyres in the morning and at the start of the second session.
The soft tyre runs, where the fastest lap times were set, were carried out in the first half of the session. The Mercedes went to them early on, when the track was still improving, Rosberg finding almost a second compared to the medium tyres. Others gained up to 1.5 seconds, especially the Ferraris.
Switching to the soft tyres a little later, Felipe Massa did a clean lap, 4/10ths faster than his team mate Alonso. The Spaniard is keen to avoid being outqualified by Massa here, as that would be the fifth time in a row, something that has never happened to him before in his F1 career. Raikkonen split the Ferraris on his soft tyre runs.
Massa in particular looked like his old self on the soft tyre, making the most of the increased grip levels it offers. Later in the session on the medium tyres his lap times were good.
The tyre degradation on the Ferrari also looks encouraging. There were signs from the tyres of Button’s McLaren after its new tyre run that the car was understeering a little, leading to more damage to the left front tyre than some of its rivals. Later in the session Button suffered what he believed to be a delamination of his front left medium tyre later in the session.
Having set their times early, Mercedes concentrated on race preparation; long runs, covering a lot of laps to make sure that they have good data for strategy planning for Sunday’s race. Hamilton did the most laps of anyone, with good medium tyre performance, looking like Mercedes were preparing for a two stop race, as they did last year. Hamilton did 27 laps on a set of mediums.
Red Bull’s Sebastian Vettel complained of vibrations during his long runs and mechanics were seen to grind down the top of his bargeboards, an unusual way of fine tuning the airflow mid-session!
Pirelli say that the data shows that the medium tyre is good for 20 laps in the race, which means that the race could be done in two stops, but it will be touch and go, while the soft is much faster relative to the medium than Pirelli was expecting.
With an advantage on soft of up to 1.5 seconds per lap over the medium, it will make the first stint on Sunday very interesting and will add to the spice of the race strategies. The moment when a set of new mediums is faster than a used set of softs will be crucial to establish.
Max Chilton had a frustrating session; the Marussia driver stopped out on track early on and although he managed to get out later in the session, he stopped again with fluid leaking from the back of the car.
Sergio Perez had an off in the morning, crashing at the pit lane entry in the McLaren due to low front tyre temperature at the end of a long run and he was off track again in the afternoon, although without damage.
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CHINESE GRAND PRIX, Shanghai, Free Practice 2
1. Felipe Massa Ferrari 1m35.340s 32 Laps
2. Kimi Raikkonen Lotus 1m35.492s + 0.152s 32
3. Fernando Alonso Ferrari 1m35.755s + 0.415s 30
4. Nico Rosberg Mercedes 1m35.819s + 0.479s 35
5. Mark Webber Red Bull 1m36.092s + 0.752s 31
6. Jenson Button McLaren 1m36.432s + 1.092s 29
7. Lewis Hamilton Mercedes 1m36.496s + 1.156s 39
8. Adrian Sutil Force India 1m36.514s + 1.174s 32
9. Paul di Resta Force India 1m36.595s + 1.255s 33
10. Sebastian Vettel Red Bull 1m36.791s + 1.451s 27
11. Sergio Perez McLaren 1m36.940s + 1.600s 16
12. Romain Grosjean Lotus 1m36.963s + 1.623s 31
13. Esteban Gutierrez Sauber 1m37.103s + 1.763s 22
14. Daniel Ricciardo Toro Rosso 1m37.206s + 1.866s 39
15. Jean-Eric Vergne Toro Rosso 1m38.127s + 2.787s 34
16. Valtteri Bottas Williams 1m38.185s + 2.845s 18
17. Nico Hulkenberg Sauber 1m38.211s + 2.871s 32
18. Pastor Maldonado Williams 1m38.276s + 2.936s 34
19. Jules Bianchi Marussia 1m38.725s + 3.385s 29
20. Giedo van der Garde Caterham 1m39.271s + 3.931s 21
21. Charles Pic Caterham 1m39.814s + 4.474s 27
22. Max Chilton Marussia 1m43.227s + 7.887s 5