In this corner, Billy Batson's alter-ego, the original Captain Marvel, often (erroneously) referred to as "Shazam!" In the other corner, we have another Captain Marvel, often (correctly) referred to as Captain Mar-Vell.
Lessee here... they can both fly, and have superhuman strength. They also both have nifty red constumes with shiny yellow emblems on their chests, but I guess that's not too relevant. Marvel (the comic company, not either of the two characters) is more specific than DC in detailing its characters' powers; they say Mar-Vell can lift ten tons, with something called "nega-bands" that augment his strength. DC tells us that the original Captain Marvel has the strength of Hercules --- a more vague appraisal, you'll agree. However, I'd say that the Greek god of strength can lift more than ten tons. Also, Batson has the edge in skills, considering he has the wisdom of Solomon, power of Zeus and speed of Mercury.
With this wisdom, Billy boy would soon realize that Mar-Vell's wristbands were the source of some of his power and destroy them. After that, the now only slightly superhuman Mar-Vell would be very easy to send back to whatever loathesome Hell the Kree go to when they die.
End result? Marvel beats Mar-Vell.
In this case, apparently, the champ doesn't get the girl, because he's really just some dorky kid.
Next: Keep your eye out for this fight!