Until he retired a couple of years ago, Serge Eisenstein, Russia's top-notch producer-director, set the pace for film-makers in Hollywood, as well as in his own country. "Alexander Nevsky," which opened last night at the Fine Arts, marks his return to favor and to the cinema world.

If the reason for his temporary eclipse was a lack of enthusiasm for Russian nationalism, he has more than made up for it in his comeback attempt, for "Alexander Nevsky" is as intensely nationalistic a film as any which local screens have shown in recent years. Basing his story on the struggles of the heroic Russian cavalry against the invading Teutonic knights of the 13th century, Eisenstein has created a picture which is more enthusiastic than sound, more spectacular than it is well-knit.

This is not to say that "Alexander Nevsky" falls into the hackneyed routine of a cowboy-and-Indian film with a Russian accent. It's a good deal more effective than the greater part of action movies that have been turned out lately, but it's a difference of degree and not of kind. For essentially Eisenstein's film is just a "don't fire until you see the whites of their eyes" story which takes place on a Prussian plain instead of on a Boston hilltop.