No I dont think so, Argentina and Brazil are performing well and Spain might face Portugal so its hard that Spain is the best, What i see is Worldcup might be Argentina's
I believe Spain will beat Portugal tomorrow LbR. Argentina did not impress me against Mexico tonight, they could have easily have lost had it not been for the poor decision on Tevez's offside goal. Brazil have been ok, but so far no team have impressed me too much. E.g. Germany were lucky against England today!
The spain midfield is undoubtedly impressive but their defence is not their greatest strength. Puyol, Pique capdevilla and ramos can be beaten and i believe tonight ronaldo will rise to the challenge and deliver a semi shock.