The best-picture race is currently dominated by Quentin Tarantino and Martin Scorsese, two Oscar-friendly auteurs with big-budget, male-led ensemble movies.

It looks like they’ll have to make room for one more.

One of the season’s final films just crashed the race in a major way: The war spectacle “1917,” directed by Sam Mendes (“American Beauty”), was unveiled in preview screenings on both coasts this past weekend and immediately announced itself as a significant Oscar player. The movie follows two British soldiers during World War I (George MacKay and Dean-Charles Chapman) as they’re given a seemingly impossible mission: Rush through dangerous territory to deliver a message that could save another battalion on the verge of annihilation.

Though “1917” recalls other Oscar-winning war movies like “Saving Private Ryan” and “Dunkirk,” Mendes distinguishes his effort by presenting the story as though “1917” were filmed all in one single take. It isn’t — Mendes and the cinematographer Roger Deakins employ all manner of clever methods to stitch together a great many different shots — but the average moviegoer won’t be able to spot the tells, and the you-are-there verisimilitude is potent.