SUZUKA  - Sebastian Vettel slashed the Formula One title race to just four points Sunday as he stormed to victory in the Japanese Grand Prix after championship leader Fernando Alonso span out on the first turn.

Red Bull's double defending world champion escaped a chaotic start and sped away to win by more than 20 seconds ahead of Ferrari's Felipe Massa and home favourite Kamui Kobayashi, whose first podium received huge roars from the capacity crowd.

The 25-year-old Vettel, who won in Singapore two weeks ago, threw the championship wide open as he became the only man this year with back-to-back victories. With five races left, he trails Alonso 194 points to 190. Alonso, of Ferrari, was eliminated when he was hit by rival Kimi Raikkonen's Lotus at the first corner and suffered a puncture, kicking up plumes of dust as he skidded into the dirt.

As carnage ensued behind him, Vettel was left out in front and he raced to a luxurious triumph, the 24th of his career, a feat that drew him level with the legendary Argentine Juan-Manuel Fangio in the record books. Alonso has not led a race since the German Grand Prix in July and his ascendancy in the championship has been more due to consistency than outright speed. On Sunday's evidence, Vettel now has both.

"I saw the safety car at the beginning, but I had a very good start and that was very important. I knew behind me there was a crash and I saw a Ferrari was out, but wasn't sure which one," said Vettel. "Halfway through I was looking to see the others and I saw their (Ferrari) car still racing. It was Felipe, I didn't know what happened to Fernando."

Only once in the previous 17 years has the winner of the Japanese race not won the title -- Ferrari driver Rubens Barrichello in 2003, the season when Michael Schumacher won a fourth successive drivers' title. But Vettel warned there was much racing left in a unpredictable championship which now has every chance of going down to the wire.

"It was an important step today, but there is still a long way to go," Vettel said. "Look at the last couple of races and since Spa (Belgium) -- it's been very much up and down. We don't know what will happen in the next race, but let's try and take the points. It's been a long season with crazy racing."

Alonso criticised Raikkonen for his first-lap mistake and admitted he'd now been plunged into a tight race for the title. "We have five races and they will be like five finals, five championships -- a big fight every time now," he said.

Massa's podium finish was his first in 35 races, and may help the under-fire Brazilian retain his seat in 2013. But his success was overshadowed by the rapturous welcome that greeted Kobayashi. In emotional scenes, the crowd chanted "Kamui, Kamui" until the driver, keen not to disappoint them, appeared on the podium with a broad, if bashful, smile and a big wave.

Jenson Button finished fourth for McLaren ahead of his Mercedes-bound team-mate Lewis Hamilton, with Raikkonen sixth behind the two Britons. Nico Hulkenberg of Force India came home seventh ahead of Pastor Maldonado of Williams and Australians Mark Webber of Red Bull and Daniel Ricciardo of Toro Rosso. The retirement-bound Michael Schumacher finished 11th.

On a warm and dry day with a track temperature of 32 degrees Celsius (90 Fahrenheit), Vettel made a perfect start and drew clear of the pack -- but behind him, it was mayhem. In a thunderous burst of collisions, similar to the start of last month's Belgian race, both Alonso and Nico Rosberg of Mercedes were knocked out while Webber was also forced off the circuit, but recovered.

Webber was shunted by Romain Grosjean of Lotus, who was hit with a one-race ban after the Belgium pile-up, and Rosberg was the victim of a mistake from Williams' Bruno Senna. Both offending drivers were given drive-through penalties.

Webber later called Grosjean "a first-lap nutcase" and said "maybe he needs another holiday". When the safety car withdrew, Vettel streaked away in front followed by Massa and Sauber's Sergio Perez, who will replace Hamilton at McLaren next year and raced with great vim before making a mistake and spinning out.

Vettel, revelling in the performance of his Red Bull, simply romped away. Button was breathing down Kobayashi's neck at the finish but the Japanese held on to ignite the home crowd.