Champions Red Bull and Sebastian Vettel have promised there will be no letting up until the end of the season even if both Formula One titles are in the bag already.After a dominant victory in Sunday's Italian Grand Prix, the 24-year-old Vettel can become the sport's youngest double champion as soon as the next race in Singapore on Sept. 25 if results go his way.     Vettel has a 112-point lead with only 150 still to be won and his rivals have all recognised the battle is over. Red Bull are 126 clear of McLaren in the constructors' standings."Our approach to Singapore will be exactly the same as every grand prix so far this year," team principal Christian Horner said afterwards."We will go there to try and win it. He (Vettel) came close last year, it would be great to win that race. And the championship will take care of itself at the end of the day."Our philosophy has been to attack each grand prix weekend and not cruise and collect points. I think that's the right philosophy and we continue to learn very valuable lessons for next year."Red Bull also have their own ambitions, with Sunday's win equalling the tally of 23 achieved by Tyrrell in that great team's entire F1 existence between 1970 and 1998.Four more wins would lift them level with Benetton in the record books."Our philosophy is you can always learn so we'll keep pushing all the way to Brazil (the last race of the season)," said Horner.Horner denied the team had any victory T-shirts or caps ready for a Vettel title in Singapore, although they are sure to be immediately in evidence if he does win it there, and Marko said they would be relaxed if the championship remained mathematically open for longer."Singapore or Japan would be fine, but I would probably prefer Korea," he said."After that disastrous weekend we experienced there last year it would be a sort of compensation."Neither Red Bull driver finished that race, their season's low before the high of Vettel's title triumph in Abu Dhabi. From/ Goalzz