The film took in $3.2 million in Japan in it's second weekend there passing the $10 million mark.
The only films to surpass Godzilla's opening take were sequels to other films, Captain America 2, Amazing Spider-man 2, X-Men, and the 4th Transformers film. Guardians of the Galaxy is close but official numbers aren't final yet (est. $94 million vs. $93.2 for Godzilla).
Godzilla is also 5th overall, interestingly Godzilla is the only one of the top 5 that didn't have at least a two week period before the next big film hit (X-Men opened a week later).