Button wins chaotic Chinese Grand Prix

The reigning world champion once again benefited from an early tyre call - this time staying out on slicks in the rain while most pitted for intermediates - and showed his class again from the front.

Even when a safety car period eradicated the lead his tyre gamble had earned him, he kept his head in tricky conditions and even stretched away from McLaren team-mate Lewis Hamilton in the closing stages when it came down to who had looked after their tyres the best.

But far from being a race of nursing the cars home, for close to 90 minutes it was frantic stuff as the weather once again played havoc with Formula 1.

The drama started early when Vitantonio Liuzzi lost control of his Force India under braking, spun and collected the Toro Rosso of Sebastien Buemi and Kamui Kobayashi's Sauber.

Adrian Sutil, Jaime Alguersuari and Rubens Barrichello were also involved and headed for repairs in the pits, while Nico Hulkenberg did well to pick his way through unscathed.

But the safety car was still required, prompting both Red Bulls, both Ferraris, Hamilton and Michael Schumacher to gamble on changing to intermediate tyres.

Initially, it looked like the right call as Fernando Alonso charged past cars still on slicks. But Nico Rosberg and Button, up front having stayed out on slicks, were lapping faster just one tour later as the inters cooked quickly with the circuit not quite wet enough for them.

Within a couple of laps all those to take them were back in the pits for slicks, leaving Rosberg, Button, Robert Kubica and Vitaly Petrov well ahead of the rest.

The stops included Hamilton and Sebastian Vettel racing each other into the pitlane and leaving side-by-side too, an incident that will be investigated later.

No sooner had the likes of Hamilton and Vettel fought their way back up the order that the rain started again, heavier this time. Leader Rosberg was caught out and a brief off-track excursion allowed Button a run at him to take the lead, and soon after everyone was in the pits to get inters back on.

The rain gifted Button, Rosberg and the Renaults a free pitstop, so the leaders 50-second advantage remained. But the safety car was back out after Alguersuari clipped the back of an HRT car and left front wing debris scattered on the track.

Button bunched the pack right up for the restart and, with the new rule about overtaking from the pitlane line, rather than the start/finish line, Vettel tried to take advantage to mug Hamilton into the last corner. But it backfired for his Red Bull team as he only succeeded in forcing Hamilton wide and shoving Webber off the track on the outside, costing the Aussie several places.

Hamilton once again had to make his way back to the front and his journey included a great battle with Schumacher. The old hand defended brilliantly for the first few advances, despite struggling for traction in his Mercedes. But eventually Hamilton made it stick with an opportunistic dive between Turns 8 and 9 - something that became his staple move of the day.

He then caught and passed Rosberg for second, just before the field descended on the pitlane once more for a final fresh set of intermediate tyres.

Things eventually settled down for the last 20 laps, as Button kept Hamilton at a safe distance. There was just a brief scare four laps from home when he overshot the final hairpin. But Hamilton was also struggling to keep his car on the road with fast-balding inters.

Rosberg couldn't quite challenge for the victory but had no trouble keeping Fernando Alonso at bay for third - the Spaniard getting in reach of the podium despite five pitstops, including a drive-through for jumping the start.

Kubica continued Renault's good form, capitalising on his early decision to stay on slicks to hold onto fifth. Vettel looked like homing in on Kubica in the closing stages but never threatened.

Webber had another day of missed opportunities and couldn't make his way forward at the same rate as Hamilton or Vettel, but he also had his share of misfortune. Already down the order he gambled on an earlier final stop, but it just left him in more tyre trouble than most come the end of the race and he was mugged for seventh by Petrov two laps from the end.

Some wise calls and excellent race craft kept Schumacher in the hunt in spite of his lack of pace. But when the race finally settled down he had no answer and was jumped late by Petrov, and then by his former Ferrari team-mate Felipe Massa on the final lap - the latter once again failing to impress in a chaotic wet race.

PROVISIONAL RACE RESULTS

The Chinese Grand Prix
Shanghai International Circuit, China;
56 laps; 305.066km;
Weather: Mixed conditions.

Classified:

Pos  Driver        Team                       Time
 1.  Button        McLaren-Mercedes           1h44:42.163
 2.  Hamilton      McLaren-Mercedes           +     1.530
 3.  Rosberg       Mercedes                   +     9.484
 4.  Alonso        Ferrari                    +    11.869
 5.  Kubica        Renault                    +    22.213
 6.  Vettel        Red Bull-Renault           +    33.310
 7.  Petrov        Renault                    +    47.600
 8.  Webber        Red Bull-Renault           +    52.172
 9.  Massa         Ferrari                    +    57.796
10.  Schumacher    Mercedes                   +  1:01.749
11.  Sutil         Force India-Mercedes       +  1:02.874
12.  Barrichello   Williams-Cosworth          +  1:03.665
13.  Alguersuari   Toro Rosso-Ferrari         +  1:11.416
14.  Kovalainen    Lotus-Cosworth             +     1 lap
15.  Hulkenberg    Williams-Cosworth          +     1 lap
16.  Senna         HRT-Cosworth               +    2 laps
17.  Chandhok      HRT-Cosworth               +    4 laps

Fastest lap: Hamilton, 1:42.061

Not classified/retirements:

Driver        Team                         On lap
Trulli        Lotus-Cosworth               27
Di Grassi     Virgin-Cosworth              9
De la Rosa    Sauber-Ferrari               8
Buemi         Toro Rosso-Ferrari           1
Kobayashi     Sauber-Ferrari               1
Liuzzi        Force India-Mercedes         1
Glock         Virgin-Cosworth              1


World Championship standings, round 4:                

Drivers:                    Constructors:             
 1.  Button        60        1.  McLaren-Mercedes          109
 2.  Rosberg       50        2.  Ferrari                    90
 3.  Alonso        49        3.  Red Bull-Renault           73
 4.  Hamilton      49        4.  Mercedes                   60
 5.  Vettel        45        5.  Renault                    46
 6.  Massa         41        6.  Force India-Mercedes       18
 7.  Kubica        40        7.  Williams-Cosworth           6
 8.  Webber        28        8.  Toro Rosso-Ferrari          2
 9.  Sutil         10       
10.  Schumacher    10       
11.  Liuzzi         8       
12.  Petrov         6       
13.  Barrichello    5       
14.  Alguersuari    2       
15.  Hulkenberg     1       
       
All timing unofficial