Coming into Sundance, we had a feeling the coming-of-age dramedy An Education would probably be pretty good. But as 282 lucky ticketholders at Sunday's premiere soon discovered, "good" isn't the half of it.

An Education all but blew the marquee off the Egyptian Theater, where over 100 latecomers were turned away onto a swarming Main Street before director Lone Scherfig nervously announced not even she had yet seen her film outside the lab. She had nothing to worry about: Led by 23-year-old Carey Mulligan in a breakthrough that makes Ellen Page's Juno turn look like a Lifetime reject, Scherfig's ensemble cast wrings a spry, otherworldly beauty from Nick Hornby's script and its corrosive glare at early '60s London. We have no idea if it's the festival's best film, as some have said, but if there is a likelier candidate for life beyond Park City —- as in awards-season, even canonical immortality — let's have it.

Mulligan plays Jenny, a middle-class 16-year-old with an eye on Oxford and a weakness for David (Peter Sarsgaard), the 30-something suitor who charms her domineering parents and introduces the girl to his swinging society lifestyle in the city. Suddenly determined to cultivate the high life, Jenny subordinates her studies in favor of romance, travel and adventure — naturally too good to be true, as David's professional and personal indiscretions soon reveal.

The chemistry between Sarsgaard and Mulligan — who yields an equally, almost unfairly sublime secondary performance in the otherwise blah The Greatest — would be enough to recommend An Education; as predatory as he is tender, Sarsgaard's David respects his intellectual match in Jenny even as he erodes her independence. And Mulligan, with a face as vulnerable and expressive as the soft smoke burnishing her voice, radiates authority even in the push-pull of submission. But abetted by supporting cast Alfred Molina, Rosamund Pike, Emma Thompson, Dominic Cooper, Olivia Williams and, in a haunting late cameo, Sally Hawkins, the lovers' respective endgames have their own charismatic coaching staffs watching from the sidelines and an able, attentive referee in Scherfig.

You can't really fuck up technically with talent like this, but you can overblow the prestige. The blockbuster Sunday premiere did neither, instead confirming Mulligan's arrival and An Education's status as one of the four or five most coveted competition titles of the festival. No sooner had the lights gone up than Sony Classics co-president Michael Barker and his deputy Dylan Leiner raced out of the theater; we hold fast to our prediction that it's their acquisition to lose, but who knows at this point, and who even cares? For another four or five Sundance audiences this week, the future is pretty much now. See it while — and whenever — you can.