FUJI SPEEDWAY, Japan, Sept 30, 2007 (AFP) - Britain´s Lewis Hamilton took a massive step towards winning the world championship with victory on Sunday in a rain-lashed Japanese Grand Prix as title rival Fernando Alonso crashed out.

The McLaren-Mercedes driver, who would be the first rookie to win the title, leads by 12 points with two races left after seeing team-mate and reigning champion Alonso smash into a wall 42 laps into the chaotic 67-lap race.

Hamilton won by more than eight seconds from Finland´s Heikki Kovalainen, who finished on the podium for the first time in his Renault career, with Ferrari´s Kimi Raikkonen third.

The 22-year-old could become the youngest driver and the first black driver to win the title in next Sunday´s Chinese Grand Prix in Shanghai.

Hamilton survived being knocked off the track mid-way through the race to claim the fourth victory of his maiden season.

"It was a very eventful race. There were so many times during the race when I am sure it went through drivers´ heads that should we stop the race. There were times when it was tricky," he said.

"I collided with Robert (Kubica). I could not see in my mirrors, my visor was all fogged up and could not see he was inside and I was fortunate to finish.

"There were lots of things going through my mind. During the last few laps I was thinking about races that (Ayrton) Senna and (Alain) Prost did. I´m feeling I am getting somewhere to achieving something similar to them."

Alonso was already struggling after being hit by Torro Rosso´s Sebastian Vettel when he skidded off the slippery track, leaving his McLaren stranded on the circuit with debris all around it.

"I´m not throwing in the towel, but unless there is a retirement from Hamilton we have to be realistic and see that it´s very hard to recover six points per race," said Alonso.

"It means winning the two remaining races and expecting him to finish fifth or sixth, so realistically it´s very complicated and we´ll need a retirement from him and he hasn´t had any this year, but maybe it will come in the last two races."

It was the first time since Brazil in 2003 that a race had to be started under the safety car because of the atrocious conditions, with heavy rain hitting the track and Mount Fuji covered in fog.

The drivers were forced to drive carefully through the spray and puddles in around two minutes 13 seconds a lap -- some 40 seconds slower than the pole winning time set by Hamilton in qualifying.

The Ferraris of Raikkonen and Felipe Massa had a nightmare time in the opening laps after neither started on full wets despite a ruling all drivers should because the race began behind the safety car.

Massa slid off on the second lap and pitted at the end of the lap for full wets while Raikkonen came in next time round and dropped down to 21st, one place behind his team-mate.

The safety car was recalled after 19 laps, just as the first F1 race at the Fuji track in 30 years was threatening to turn into a washout.

The conditions had not improved and Williams driver Alex Wurz did not make it past the first corner before sliding off and clipping Massa as he returned to the track.

Alonso was the first to make a pit-stop at the end of lap 27, with Hamilton stopping one lap later leaving Vettel, who had qualified a career-best ninth, leading a race for the first time from Webber.

Double champion Alonso slid off on lap 29 and although he managed to get back on the track he lost several more seconds to his team-mate.

But Hamilton was then taken off the track by Robert Kubica in the other BMW. The Pole picked up a drive through penalty as Hamilton dropped to fourth.

Hamilton regained the lead on lap 40 as the others pitted before a thrilling championship battle took another twist on lap 42 when Alonso crashed out.