Lincoln Center’s fashion scrum: After Labor Day, can’t wear light clothes. Early September, can’t wear heavy clothes. For Carolina Herrera’s glorious show, guests wore shorts, sleeveless and sweaters. Spikes, boots, flip-flops. Skirts, navel-length and ankle-length. It was 57 degrees. My seatmate Martina Navratilova was in all-over black with a jacket.

Martina on Serena Williams lacking one trophy to equal hers: “She’s a great player. But at her age I contended with Steffi Graf. Serena has no Steffi Graf.”

And where’s her trophies? “In boxes. In a room in my Miami home. I’m busy lecturing. I have two children. No space. And no time.”

Then: “I’m told Carolina’s show is only 9¹/₂ minutes. Like a tennis match.”

Lovely Crowd

Ralph Rucci’s stunning collection brought socialites from Susan Gutfreund, who’s decorating palaces in Europe, to faces like eternal model Carmen Dell’Orefice. Our longest-working mannequin, 82, silver-haired Carmen, posing for photos, said: “Thank God they’re asking me. Otherwise I’d think I was dead.”

Floor-side, gazing up at tiers of people, I stared straight into one lady, legs apart, with a hem above her blouse. I could actually see what she was thinking.

Spanish Influence

Joanna Mastroianni, whose collection’s at Bergdorfs, took ideas from a trip to Barcelona. Solid beaded gowns in orange, turquoise, yellow. Overall ostrich feathers. Handmade designed accessories. The models’ hairstyles all sleek tight sky-high fake ponytails. Said one fashion pro: “She’s the best. She’s magnificent. Her work is so precise.”

’50 Shades of Casting Revealed

Casting “50 Shades of Grey” was difficult because of its steamy scenes. Casting director Sheila Jaffe, now doing “McFarland,” Kevin Costner’s true story for Disney that shoots next month, explained how the operation works.

“This is about an ’80s Midwest coach teaching Mexicans football. I’m hunting seven Mexican boys. High school age, must excel at running. You start investigating various places. Photos, agents, producers, movies they maybe made, improv groups, children of Latino stars. You check with drivers, extras, hair and makeup people. Dig into your memory bank. Studios weigh in. Lots of list-making.

“With Mark Wahlberg’s ‘The Fighter,’ I went through everything. Called everybody. Finally back to some years-ago movie I came up with Christian Bale. When I did ‘The Sopranos,’ by luck the very last day before shooting began I remembered one New York guy, Jerry Adler, and he stepped in as the older Jewish gangster.

“For ‘Entourage,’ I saw so many people. I could never find the right one. When Kevin Dillon read, we knew he was It. Kevin Connelly I knew as a teenager. Adrien Grenier I’d seen at some off-off-off-Broadway tiny little play and I cast him.”

How did she start as a casting director?

“I hostessed at 75th and Amsterdam’s tiny Café Central. Bartender Bruce Willis moonlighted off-Broadway and got in Sam Shepard’s ‘Fool for Love.’ And then we were both off and running.”

Here’s a Miss and a Hit

Sunday 4:55 p.m., across CNN’s screen: “Histrory of Surrent Negotiations.” Nice . . . And won’t everyone say how terrific East 44th’s restaurant Padre Figlio is? Italian menu, nighttime music, excellent service.

So after a massage and facial, this well-known lady’s coif was mussed. Anticipating such in advance, she’d prepared by bringing along a wig. Late for lunch, she fast slapped it on. Rushing in, the man with whom she was lunching whispered: “Your wig is on backwards.”

Only in New York, kids, only in New York.