Call it the weak-knees defense.

The owner of the famed Da Silvano Italian restaurant in Greenwich Village is trying to beat back a sex-assault suit by contending that he’s too old and feeble to grab anyone’s cannoli.

Silver-haired Silvano Marchetto notes in court papers that he’s “a 65-year-old man with health problems, bad knees, and has even suffered a stroke.”

So he says it’s “shocking” that 6-foot-2-inch, 250-pound Samuel Cruz claims he “could not defend himself” when Marchetto allegedly twice groped Cruz’s genitals at a parking garage near the restaurateur’s celeb-friendly, Tuscan-style eatery.

Marchetto — who is married to cartoonist Marisa Acocella Marchetto — also says Cruz’s Manhattan federal court case should be tossed because he hasn’t provided “any direct evidence, medical or otherwise, as to the approximate damages” he allegedly suffered.