"No surprises: they have the fastest package," BBC Sport quotes the Spaniard as saying. "But we put more pressure on them on Sundays. We will take our opportunities and fight every lap in the race."
"[Red Bull] are first and second in all the practice [sessions] and in qualifying, and if everything goes normal first and second in the race - but in the race sometimes everything is not going normal.
"We know their strong point is the speed of the package and our strong point is the united team, we try to use our strong points."
Alonso added that he is "convinced" that he can overtake Vettel in the championship race.
"The important thing is to score 11 more points than them in these two races," he said.
"We are still convinced we can do it. But we are not surprised when they are first and second in practice and qualifying."
Alonso last won the world championship in 2006.