SINGAPORE (AFP) Red Bulls Mark Webber might still be favourite to clinch the Formula One drivers title, but Fernando Alonso has other ideas after his stirring victory in the Singapore Grand Prix. The Ferrari star scored a vital win under the lights of the Marina Bay street circuit, holding off a full-race charge from Sebastian Vettel, to leave the championship wide open with four races to go. Webber leads with 202 points ahead of Alonso on 191. McLarens Lewis Hamilton, who failed to finish for the second race in a row, has 182 with Vettel a point further adrift and reigning world champion Jenson Button on 177. Alonso has now scored more points than anyone else over the past five races to put him in firm contention for a third world title and he fancies his chances. I think it remains very tight. All five contenders still have the same possibilities, he said. Mark has a little bit more with still some margin to have a bad weekend not putting at risk the contention of the championship. For the others we need to keep catching if we can. We will do our best. We do not know if it will be enough to become champion in Abu Dhabi. But we will give 100 percent. Hopefully it is enough but people can be sure we will fight until the end. The Spaniard, who won his 25th race on Sunday, added that it was inevitable that Ferrari, Red Bull and McLaren would have ups and downs between now and the last race of the season in Abu Dhabi. Having a championship that is nine months doesnt happen in many other sports, he said. We are a sport where you cant be 100 percent fit and focused for all races, we go up and down and thats normal. But I can say now that I am at a peak in motivation and concentration. This year it feels like the championship is starting now. Webber has never been world champion and the 34-year-old Australian is desperate to put that right. After colliding with Hamilton on Sunday, he rode his luck to finish third and stay in the driving seat for the title. It has been a pretty difficult weekend here to be honest for me. Probably the toughest weekend of the year for me, he said. In Monaco it was the other way around on a street circuit. I felt incredibly comfortable. Did not feel mega-comfortable here most of the weekend but very, very happy with how the race went for me. Of course Fernando is still hanging in there, so (we) need to try and get rid of him somehow, but it is going OK. Hamilton was seen as favourite for the championship before his retirement in Monza two weeks ago, and his failure to bag any more points in Singapore has seriously dented his title ambitions. But the Briton remains optimistic, and isnt ready to give up. There are still four races to go. Im 20 points behind Mark, and thats a reasonable gap, but its not an insurmountable one, said Hamilton, who won in Singapore last year. I guess Ill just have to keep my head down and hope for the best. The Formula One circus moves to Japan next, on October 10, and then South Korea is scheduled to host its inaugural race, although concerns remain as to whether it will be ready in time. The sports supremo Bernie Ecclestone told the BBC on Sunday it was not clear whether the event would go ahead, with an official inspection that was due last week postponed. After that comes Brazil before the finale in Abu Dhabi.