To borrow a term from Sheldon Cooper: bazinga. The Good Doctor’s third episode on ABC beat out The Big Bang Theory’s broadcast from last week, making the freshman medical drama the most-watched program of the night—and one of the few shows ever to win in a head-to-head battle with CBS’s ratings juggernaut.

18.2 million viewers tuned in to watch Freddie Highmore play doctor, while The Big Bang is sitting on a mere 17.9 million. And lest you think that Good Doctor’s viewers are all senior citizens who fell asleep watching Dancing with the Stars, make no mistake: the series also scored a 4.2 rating in the key 18-49 demo—just 0.3 below Big Bang. We’re guessing ABC is thrilled—but for those of you scratching your heads and wondering how this possibly could have happened, we’ve got some theories.

First, there’s the obvious: hospital procedurals are a perennially popular genre, and TV has not successfully launched a new one in a long time. Right now, broadcast networks are basically down to a single show about attractive doctors: Grey’s Anatomy, which also airs on ABC. The network is basically all Grey’s and Good Doctor have in common, however. Unlike Meredith Grey, Highmore’s Dr. Shaun Murphy is male, obviously; perhaps more importantly, he’s also autistic. The show’s pilot centered on whether the hospital should even hire Murphy, given that fact; even after the board ultimately voted to bring him on, Murphy’s first day as a surgical resident mostly entailed doing other residents’ scut work. A lot of the humor so far—the show does have humor!—has stemmed from Murphy’s atypical social understanding and his unintentional bluntness. Still, he’s unquestionably a gifted surgeon who often catches things his colleagues overlook. If anything, The Good Doctor feels like a more tender, earnest version of House.

That earnest streak likely helps the series, too. Given the bleak national mood, it’s easy to understand the appeal of a story about a determined, kindhearted doctor overcoming discrimination; just look at what a similar tone has done for This Is Us. It also doesn’t hurt that Highmore, who turned in a consistently great performance on Bates Motel, is similarly magnetic in this role. He’s also managed to find empathy in the comedy that comes from Murphy's social misunderstandings, rather than simply playing his character’s limitations for laughs.

And finally: The Big Bang Theory has been plugging along for over a decade now, so it’s only natural that its once-impenetrable ratings domination has begun to crack. We’re guessing that between the still-strong ratings and its successful spin-off, Young Sheldon, CBS is still feeling fine—but in the race to secure the title of the fall season’s most-watched show, CBS’s nerds and NBC’s beloved weepy might have some some real competition in a white coat.