Brazil v Argentina in the final would be amazing - the clash of two sub-plots.
In their first Maracana WC game since 1950, Brazil will be desperate to finally avenge Maracanazo. The pressure on them is enormous.
Then there's Messi, who everyone says has to win a WC to be considered the best of all time. He's dragging them there so far.
If they do meet, one of these has to give way. It'd be a huge and probably thrilling final.