MIAMI—Throughout the regular tennis season, ATP and WTA athletes know Hard Rock Stadium—normally the home of the NFL’s Miami Dolphins—as the site of one of the tour’s premier combined 1000 events.

But on Monday night, Carlos Alcaraz, Amanda Anisimova, Joao Fonseca, and Jessica Pegula traded their usual setting for a new stage, stepping into an MLB ballpark for the first-ever Miami Invitational during the off-season.