Highlights - Button wins Australian Grand Prix (UK users only)
Jenson Button won an incident-packed Australian Grand Prix after the leading Red Bull of Sebastian Vettel slid out of the race with brake failure.
An early swap to dry-weather slick tyres proved crucial in a race dominated by changing weather, crashes and breathtaking racing.
Vettel's lead looked secure until his mid-race problem allowed Button in.
A stubborn Robert Kubica claimed second for Renault, holding off the Ferraris of Felipe Massa and Fernando Alonso.
Button's team-mate Lewis Hamilton was challenging Alonso for fourth in the closing stages but finished up sixth after a collision with the Red Bull of Mark Webber.
The Australian clattered into the back of Hamilton's car when he misjudged his braking as Hamilton pulled out of an attempt to pass the Ferrari with two laps to go.
Hamilton was fighting back after a decision by McLaren to bring him in mid-race to fit new tyres.
It made Hamilton much faster than those in front of him, who were still on the tyres they had fitted in the early laps as the track dried following a wet start. But he was frustrated in his attempts to pass and blamed his team for making a mistake on strategy.
"It was one of the drives of my life," Hamilton said. "Unfortunately because of the strategy I got put back and then I drove my heart out today and I think I deserved better. Everyone else in front of me did one stop and I did two."
Win feels pretty special - Button (UK only)
In a sign of the drama to come, positions at the front of the pack were immediately jumbled into the first corner, with Massa making the biggest gain as he took advantage of the dry side of the track to pick his way up from seventh to second.
Alonso made a slow start from third on the grid and fell to the back of the field after tangling with Button at the first corner, while Hamilton moved up to seventh from 11th and Vettel kept clear of the raging battle behind him.
But the race's crucial strategic decision was soon to follow from Button on lap six.
The defending world champion had seen Hamilton sweep past and into sixth but more than made back the ground by stopping for dry-weather tyres.
Despite slipping off the track as he emerged from the pits, Button's decision was vindicated as he took more than two seconds off the previous fastest lap by Vettel and moved into second as the rest of the field pulled into the pits a lap later.
Australian GP driver news conference (UK only)
"It was my call, it is a lot easier for the driver to feel the conditions," said Button on the timing of his first stop.
"When I entered the pit-lane I thought I had made a catastrophic decision because it was soaking wet in the pit-lane, but once I got it going and up to speed the pace was pretty good."
However, Vettel looked to have the beating of Button before a repeat of his failure to convert pole position into victory in the season-opener in Bahrain.
The German ploughed into the gravel on lap 26 after a wheel failure on Turn 13 and, with clear track in front of him, Button built a 12-second lead over Kubica in second.
Pit-lane traffic had prevented Hamilton matching his team-mate's gains on his first stop and he was drawn into an engrossing four-way battle as he jostled with Webber, Massa and Alonso for fifth.
It seemed he had emerged victorious after watching Webber slide wide in front of him, stalking down Massa and slipping past third-placed Nico Rosberg with a daring move into the 150mph turn 11.
The 2008 world champion fell to fifth as he took new tyres on lap 34, but it appeared the decision may pay off as he closed on Alonso towards the end.
Having made his way up from 22nd place after the first lap, the Ferrari driver's climb up the field had been held up as team-mate Massa struggled to get close enough to launch a strike at Kubica.
But Hamilton was ultimately fortunate to finish the race after his aborted pass was swiftly followed by a significant shunt for which Webber was reprimanded after the race.
Hamilton frustrated by 'wrong' strategy
Michael Schumacher's underwhelming return continued as he trailed home 10th after spending much of the middle part of the race trapped behind the Toro Rosso of Jaime Alguersuari.
Schumacher's former team Ferrari now occupy the top two positions in the drivers' standings with Alonso on 37 points, four clear of Massa, with race-winner Button third on 31 points.
Despite starting from pole in each of the season's race so far, Vettel heads to the next race in Malaysia on 4 April 25 points adrift of Alonso.