Fernando Alonso does not think Ferrari can end its 2013 campaign by finishing runner-up to dominant champions Red Bull.The team is sandwiched between Mercedes and Lotus in the lucrative Constructors' World Championship with just the Brazil finale (November 24) to run.'TOO HIGH A GOAL'Alonso said continuing to fend off Lotus is all Ferrari can realistically hope for: "There is nothing more we can do in this moment."We are fighting to be in Q3 and scoring points on November 24. Maybe it (finishing second) was just too high a goal. You have to be realistic and realise that second place was a dream." While acknowledging that Ferrari's 2013 car is slower than Mercedes and Lotus, Alonso said he is proud of his personal performance in 2013.Indeed, in Austin, he mathematically clinched the runner-up spot behind Sebastian Vettel in the drivers' chase.Alonso said: "I am proud because we clearly do not have the second fastest car. So finishing second is a great reward for me. I would rather be tenth ten times and once champion, than to always finish second." BRAZIL PREPARATIONAlonso said: "My preparation for this race (the US GP) was not ideal. I was a week on the couch and in bed with headaches, dizziness. Physically I feel tired now and I felt stress throughout the weekend."I think I'll be fine for Brazil, I am improving day by day and hopefully I feel a little better, less tired and I enjoy the weekend some more."