Dragon Ball Super: Season 4, Episode 4

4 - 4: Goku VS Black! The Road Towards The Sealed Future

Goku Black arrives in the past, expressing an interest in fighting Goku and is able to hold his own against his Super Saiyan form while Future Trunks wonders why Goku is holding back. The fight continue until the time distortion caused by the Time Capsule begins to fade, weakening the time tear as Black is being dragged back to the future. But he destroys the Time Machine as his final act in the present, Whis revealing Black used a Time Ring (時の指輪, Toki no yubiwa) that only Supreme Kais possess. But he and Beerus are astonished when Bulma reveals that she kept the other version of Time Machine that Cell used to travel back in time, intending to use her future self's journal to repair it. Just as Black reappears in the future timeline, Future Mai regains consciousness.