Hillary Clinton has met a fair amount of belligerence on the campaign trail this year, and she’s just days away from facing down Donald Trump at the first presidential debate on Monday—an occasion that will probably require steely serenity in the face of angry lunacy. So what better preparation for her than chatting with Zach Galifianakis on Between Two Ferns, the comedy world’s most intense test of a celebrity’s patience for asinine questions?

In a new segment from Galifianakis’s intermittent Funny or Die series, released Thursday morning, the comedian’s typical brand of maddening, hilariously rude repartee met Clinton at her most deadpan—and, not coincidentally, her funniest. The candidate has done plenty of comic appearances in her long career, but like so many politicians, she can often feel stilted when doing scripted comedy bits. The semi-improvised Between Two Ferns is designed to provoke awkwardness, strange pauses, and annoyed glares from its guests. Clinton leaned into that perfectly, responding to Galifianakis with the kind of polite indifference that made it feel like she wasn’t trying too hard to be in on the joke.

Clinton made a softball appearance on The Tonight Show recently, and it was the kind of unmemorable, uneventful celebrity cameo that show seems to aim for, beginning with Fallon jokingly donning a surgical mask to poke at her recent pneumonia diagnosis. Between Two Ferns also tipped its hat to recent news: The interview started with Galifianakis approaching the candidate dressed as the Grim Reaper, before being tackled by her security detail. “Not a good idea around the Secret Service,” Clinton noted, giving the bedraggled comedian a slow, considered blink, with just the hint of a smile. (You can guess which TV appearance was funnier.)