According to game's director Tatsuya Nakae in a 2000 Arcadia magazine #3 developer interview, he was asked how they were able to realize the support for the game's online matching service network (established in collaboration with Japanese telecom KDDI). He responded:

"In the beginning, Funamizu asked us if it’d be possible to add online battles as a major selling point, and after discussing it internally and determining that it might be feasible, we decided to approach KDDI with the idea. Thankfully, KDDI was on board and got to work on making it a reality; we didn’t have a ton of time for development, but thanks to the hard work of KDDI, we were able to make it happen."
"At first, I was worried about lag during online matches, but when we ran in-house tests, the lag didn’t feel as bad as I feared it would and we were able to comfortably play online, so we rushed to finish the game. People who’ve never tried it tend to think “online play, I don’t know…” and shy away from it, but those people are the ones who are the most impressed when they finally try it for themselves, so I’d really urge you to go hands-on for yourselves."
Contributed by ProtoSnake