SAO PAULO, Brazil - Ferrari's Fernando Alonso rates 2012 as his best season in Formula 1 but says his car must be quicker for him to challenge for the 2013 Drivers' title.Uninspiring qualifying times continually forced Alonso to weave his way up through the pack on race day, making his three victories and 13 podiums all the more impressive.FERRARI'S LUCK WON'T HOLDWrangling with a car slower than the Red Bulls and McLarens was hard for the double World champion who said Ferrari's luck would run out if a repeat happened next year.Alonso told reporters after the final and deciding race of the 2012 season in Brazil was lost to Sebastian Vettel: "For future, I think we need to improve the car. We were behind the Red Bulls, behind the McLarens, and now, in the last couple of grands prix, behind Williams and Force India."This is something we must improve next year because we cannot fight for a world championship if we are too slow."Alonso's defeat by Vettel came with a tense finale. Weather greased the track and the Red Bull spun on the first lap and Vettel fell to the back of the field.A multitude of permutations lined Alonso's path to a third Drivers' crown but his younger rival worked his way back through the field. Alonso's second place was not enough as Vettel crossed the line sixth to take the title by three points.Heading into the Belgian GP at the start of September, Alonso had a 40-point cushion over Red Bull's Australian driver Mark Webber and was on course for a third World title despite the odds of an underperforming car."Two or three bad races can make you lose everything," Alonso said in August. "We have a points advantage but a performance disadvantage so I don't think we are any favourites."Alonso failed to finish in Belgium and in Japan in October.