Rocketeers on the two platforms began intermingling as of 3pm PT/6pm ET/10pm BST today. Once the necessary patch is applied, players can also choose to opt in or out of playing with other systems by toggling a checkbox in the game's settings.
"Cross-network play has been something that Xbox One gamers have been asking us for since the day we launched, and thanks to Microsoft's new cross-network policies, we're proud to give it to them," wrote Psyonix in its official blog.
Microsoft announced back in March that it would open up the Xbox One to other platforms, with Rocket League being the first game to take advantage of the feature. PS4 owners have had PC cross-play since launch, and Sony has expressed an open - albeit non-committal - mind towards playing ball with more systems in the future.
What's next for the four-wheeled footballer? Should everything go a certain way, Psyonix would like to link up PS4 and Xbox One players so they could compete across consoles. The team even has all the technical work figured out, and is just sitting patiently for Sony and Microsoft to come to an agreement.