GREATER NOIDA, India - Sebastian Vettel has pledged to keep pushing until the very end as he aims to secure an amazing fourth straight Drivers' and Constructors' title double at the 2013 Indian Formula 1 GP.The 26-year-old Red Bull ace, who enjoys a 90-point lead over his nearest challenger Fernando Alonso, needs only to finish among the top five on Sunday (Oct 27) to wrap up the Drivers' championship.DOUBLE WINWhile Vettel would become the youngest man to win four titles in a row - with Juan Manuel Fangio and Michael Schumacher the only others to do it - the Constructors' title is also significant. With a whopping 148-point lead, Red Bull only has to maintain a 129-point gap to seal their fourth consecutive team championship, the best run since Ferrari dominated the last decade.Vettel is on the best run of his career after winning the previous five grands prix; he also triumphed at the Buddh International Circuit on New Delhi's outskirts in 2011 and 2012. but despite his unstoppable form he is not taking anything for granted. "It looks very good at this stage,," he admitted, "but it's not over before it's over. We obviously have a very, very good gap but we will still keep pushing."History will also spur on the determined Vettel as victories in India, Abu Dhabi, America and the 2013 season finale in Brazil would make him the first man to win nine races in a row in one season. He would also equal Schumacher's 2004 record of 13 victories in one year. Italy's Alberto Ascari won nine straight for Ferrari but his feat was spread over two seasons - 1952 and 1953.Vettel's absolute dominance may have earned him unsporting boos and taken the suspense out of F1 this season but his crowning could be good news for India. With the Indian GP missing from the 2014 schedule, a World title win could bring extra crowds and excitement and help ensure it returns in 2015.India's first F1 driver, Narain Karthikeyan, said: "It is great news for India that the 'coronation' of Vettel will take place here. It is one more reason for fans to come to the circuit."'MATTER OF TIME'While Vettel's winning streak owes much to his Red Bull car, he has showed tenacity and guile - and, when needed, blistering pace - to maintain his iron grip on the title. The only way Vettel can be denied is if he fails to win a point in the remaining four races - provided Ferrari's Alonso wins at least three of them and finishes second in the other. However, even as 2005 and 2006 champion for Renault, he is under no illusion that he can engineer a dramatic turnaround.Asked after the previous race, in Japan, if the fight was still on, Alonso said: "I don't think so. We will keep doing the best possible, but it's a matter of time."Lewis Hamilton, fourth in the standings behind Kimi Raikkonen and out of the reckoning for 2013, said he was willing to bet that Vettel would win the last four races. "I am willing to put money on it," said Hamilton. "Why not? He's just walking it."Vettel said he looked forward to racing at Buddh again, watched by an estimated crowd of around 50 000. "So far everything has always gone perfectly for us in India," he said. "There is also a very nice trophy at the end of the race - so it would be great to hold one again in 2013."It is not an easy track - there are a few complicated rhythm-breakers there. So, to drive a perfect lap around the Buddh circuit, you need a good driving instinct."Behind Vettel and Red Bull, the battle for No.2 in the Constructors' championship is more competitive with Mercedes 10 points behind second-placed Ferrari, and Lotus a further 23 points back. Stay with Wheels24 for the 2013 Indian GP weekend.