Double World Champion believes that Jenson Button and Brawn remain firm title favorites in 2009 despite Red Bull's strong form so far in this weekend's British Grand Prix.
"I remember last year that Mark Webber was starting second here, so this is a Red Bull circuit," said the Spaniard. "But let's wait.
"I think Brawn are still big favorites, and Red Bull is the only one who can fight for some races with them, and take some wins out of Brawn, but championship wise – apart from the gap Jenson has already – Brawn will be very consistent always.
"Even with third places Jenson will take the title, because Red Bull will not win every single race. Okay Red Bull did a step forward here, but maybe Brawn in the next race can do the step again."
Alonso said the performance extracted from the revised RB5 by Red Bull this weekend was encouraging for all the teams, but added that consistency would be the biggest factor in Red Bull's sustained challenge at the front.
"It is a good example for everybody," he said. "They did a very good car, and here this weekend they have been the quickest car – even more than the Brawn. So, Red Bull Racing is doing a fantastic job.
"But it is not an example just for Red Bull – it is an example for everybody. But, we do our own championship and we do our own performance – and also Red Bull was very quick last year in this part of the championship.
"At the end, they finished even behind Toro Rosso last year. That is not the case this year, because they are contenders for the championship as they are doing very well, but the performance is always up and down.
"Sometimes you do good, as we did last year, and sometimes you are not doing things very good as we did this year. But you just need to improve."