Samuel Beckett’s Endgame is getting a magnificent revival at Off Broadway’s Irish Repertory Theatre that is a master class in how to handle this tricky playwright’s challenging work. Thanks to the notorious persnickety Beckett estate, adaptation and updates are out of the question in a way that has benefited other classic but difficult playwrights (from Shakespeare to Tennessee Williams).

But director Ciarán O’Reilly, with an absolutely perfect cast led by Bill Irwin and John Douglas Thompson, manage the feat of presenting Beckett’s tragicomic exercise in postapocalyptic nihilism in a way that feels if not spanking-new fresh then entirely accessible. Thompson is a suitably commanding presence as Hamm, the blind and tyrannical figure at the center of the play. Like the king on a chessboard, he is both at the center of the action and limited in his actual powers, confined as he is to a wheelchair.

But he looms large over the life of Irwin’s Clov, a perpetual servant with a stiff-limbed gait who holds his own in witty exchanges with his master about the existential cloud over their existence but who cannot find the will to strike out on his own. Irwin, a famed clown, uses his gift for physical comedy to great effect here, wrestling a ladder about the stage, and stutter-stepping up said ladder to swing his leg over the top run and perch himself if on a saddle as he peers out through the too-high windows that mostly offer views of brick walls. (The wonderfully gloomy set design is by Charlie Corcoran, thoughtfully lit by Michael Gottlieb.)

The production offers other moments of slapstick, including Clov retrieving Hamm’s stuffed dog (designed by Deirdre Brennan), a three-legged companion who immediately face-plants when placed at Hamm’s feet. More bits of levity (and dread) come from Hamm’s parents, who emerge like Oscar the Grouch from onstage garbage cans but are unable to either escape nor fully embrace each other. Joe Grifasi and Patrice Johnson Chevannes are brilliant in the roles, offering an elderly counterpoint to Hamm and Clov as they are aggrieved one moment and resigned the next.

We never learn what has happened to the world outside to produce the current hellscape, nor exactly what has befallen our central characters. Beckett’s interest is in how humans cope in the midst of despair, and the answer seems to be through some combination of avoidance, engagement through conversation, constant complaint and outright farce. It’s the latter quality, from that three-legged stuffed dog to the shrillness of the whistle that Thompson’s Hamm uses to summon Clov, that O’Reilly smartly leans into here. It’s as if he has taken to heart the message from Hamm’s mother: “Nothing is funnier than unhappiness, I grant you that.”