"George Balanchine once said, 'There are no new steps, only new combinations,'" Derek Lam said backstage before his show. "And I thought to myself, That's what makes his work so modern." There were no ballet references in Lam's Fall collection, but there's little arguing that the designer has found his groove in the last year or so. What Lam excels at is classic sportswear tweaked and updated with surprising, often luxe fabrics. Take, for starters, a shearling vest. Turns out that's not your average, everyday lamb shearling—it's softer, warmer alpaca. Lam has the fur-sleeve coats that have been absolutely everywhere so far this season, but his come with a difference. Make that two: First, the fur is waxed, which ups its weather-resistance quotient while simultaneously giving it a cool, almost wet look; and second, the body of the coat is hard-working cotton.

But those kinds of details aren't the only things that will make this collection so attractive to his customers. Lam gives you a reason to add another peacoat to your closet by cutting it in a gorgeous smoky blue. And if you were of the mind that you had plenty of full-legged trousers, thank you very much, the clever two-tone pair in silk-rayon and technical twill that he showed with a gold lamé necktie blouse and a flannel blazer will have you reconsidering. Same goes for his jumpsuits, which feature the new away-from-the-body silhouette Phoebe Philo's been experimenting with. For evening, Lam played matchmaker, pairing a leather bodice with a breezy poplin long-to-the-floor skirt, or strapless stretch flannel with fluid silk jersey. The off-kilter combinations only added to the gowns' appealing ease.