Jenson Button took his second victory of the year by controlling a hectic, wet 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 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.
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 Bruno’s car and left front wing debris scattered on the track.
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.
1. Button - McLaren 1h44:42.163
2. Hamilton - McLaren + 1.530
3. Rosberg – Mercedes + 9.484
4. Alonso - Ferrari + 11.869
5. Kubica - Renault + 22.213
6. Vettel - Red Bull + 33.310
7. Petrov - Renault + 47.600
8. Webber - Red Bull + 52.172
9. Massa - Ferrari + 57.796
10. Schumacher - Mercedes + 1:01.749
11. Sutil - Force India + 1:02.874
12. Barrichello - Williams + 1:03.665
13. Alguersuari - Toro Rosso + 1:11.416
14. Kovalainen - Lotus + 1 lap
15. Hulkenberg - Williams + 1 lap
16. Senna – HRT + 2 laps
17. Chandhok - HRT-Cosworth + 4 laps