A crossover between The CW's "The Flash" and CBS's "Supergirl" once looked like it might never happen, with producers and network executives playing down the possibility for months. But now that we're mere days away from the big event, Grant Gustin is already looking ahead to the next team-up.

As we've seen in the marketing for the March 28 episode of "Supergirl," called "World's Finest," Gustin's Flash and Melissa Benoist's Maid of Might find time for a race to determine who's faster -- a nod to the classic DC Comics match-ups between Superman and the Scarlet Speedster. Although executive producer Andrew Kreisberg doesn't reveal which hero wins, he does tease to EW that "It's close,"

So close, apparently, that Gustin is anticipating a rematch next season, possibly with the key players from "Arrow" and "DC's Legends of Tomorrow" cheering them on.

"That's in the cards at this point," he says "The whole point of us doing this crossover is setting up the fact that maybe next year we can cross over all of them."

The Flash/Supergirl crossover airs Monday, March 28, at 8 p.m. ET/PT on CBS.