Godzilla: King of the Monsters director Michael Dougherty has been taking to social media to reveal Easter eggs and production trivia about the tale of rampaging kaiju, such as references to the Toho movies, Mothra not being allowed to kill anyone, or an original plan for Rodan to team up with Godzilla and Mothra against King Ghidorah. In addition, he’s confirmed a fan theory about the great lizard’s second battle with nemesis King Ghidorah.
During the face off with the alien menace, the Navy launches its Oxygen Destroyer missile with the intention of eliminating both creatures and ending the Titan threat, only for the dragon’s extraterrestrial physiology rendering it unaffected by the weapon, while the nascent king of the monsters barely survives and has to retreat to his sunken city lair to recuperate. The theory states that had the puny humans not attempted to intervene, Godzilla would have emerged victorious, which Dougherty has confirmed via the movie’s official Twitter account.
For the record, since they were fighting on Godzilla's underwater turf, Godzilla would've won this fight and eaten Ghidorah for dinner if humans didn't stupidly interfere (again). We never learn…
— Monsterverse (@Monsterverse) April 24, 2020
It was clear that Godzilla had the upper hand in the fight, being far more adapted for sub-aquatic combat than a creature built for flight, and right before the missile’s impact he had just ripped off one of Ghidorah’s heads, and was presumably about to make quick work of the other two and leave the whole movie an hour shorter.
Dougherty isn’t necessarily stating that Godzilla is intrinsically more powerful than Ghidorah, but that the circumstances of the fight heavily favored the former. During the movie’s climax on dry land, it took the combined power of a thermonuclear explosion and the energy from Mothra’s dying sacrifice to grant him the strength to overcome the triple-headed behemoth.
With Godzilla: King of the Monsters ending with Gojira’s ascension to his metaphorical throne, he’ll face the first challenger to his crown in the shape of King Kong, where we’ll see who emerges victorious in his smackdown with the primordial primate, and on which side of the battle humanity will stand.