The gone-too-soon passing of the great Canadian funnywoman Catherine O’Hara last week had an added touch of pathos about it that other great comedians could appreciate — the timing.

O’Hara went to that great Second City Alumi Reunion in the Sky on the day before the Westminster Dog Show’s annual pageant of all things “judged” about canines. Thinking about her over the weekend of “best in group/breed/show” events on the tube must have reminded many of the finest of her finest hours, “Best of Show.”

The dizzy matriarch of “Schitt’s Creek,” diva of Canada’s version of “Second City” and mom who makes guilt-ridden from leaving her kid “Home Alone” amusing was never funnier than she was in Christopher Guest’s improv also-rans in a string of films that began with “Waiting for Guffman” and ended with the uncelebrated “Mascots.” That partly-improvising ensemble comedy filmed without two of the company’s mainstays — O’Hara and her “Second City” partner in caricature, Eugene Levy — was released to no acclaim and failed accordingly.

The rep company’s “inside a dog show” comedy “Best in Show” (2000) is the funniest and most-loved of the lot. O’Hara — playing a Florida dog owner/”handler” with a torrid sexual past — was never funnier and was as cringey as the comedy legend ever got. Her dolled-up, cleavaged-down Cookie Fleck has every man over 40 that she and her buck-toothed dork of a husband Gerry (Levy) meet remembering how much of the Kama Sutra they tried out in days gone by, and the lecherous rubes are tactless enough to have those recollections in front of her hapless literal “two left feet” husband.

The Flecks compete their little Norwich Terrier all the way from Fern City, Fla. to The Mayflower Dog Show in Philly, an event set up, hosted and filmed like the long-running Westminster Dog Show in NYC.

Our mockumentary follows the Flecks,  a married pair (Parker Posey and Michael Hitchcock) whose neurotic Weimeraner has them in couples counseling, the gay couple (John Michael Higgins over-the-top bitchy/swishy, and Michael McKean) competing a Shih Tzu and the married-money golddigger (Jennifer Coolidge) who has tough broad Jane Lynch as her Standard Poodle’s handler.

A long shot? That would be a Pine Nut, N.C. good’ol boy (actor/director Guest) with showbiz aspirations and a bloodhound who is the biggest boo boo of them all.

They’re interviewed at home or in their shrink’s office, followed on the road trips to the event, captured primping their dogs and overheard at their bitchiest in the vain hope that at least some of them will be funnier than the clueless TV host for the event played by Fred Willard.

His character was inspired by dizzy ex-big leaguer turned baseball announcer, Joe Garagiola, inexplicably hired for YEARS of Westminster color commentaries,

“Now tell me,” the cocksure but clueless Buck Laughlin (Willard) asks, “Which one of these dogs would you want to have as your wide receiver on your football team?”

It’s worth noting that Guest beat Steve Carell AND Ricky Gervais to the punch with cringier than cringe mockumentary comedies. “Waiting for Guffman” sent up theater’s small-timers. “A Mighty Wind” found pathos in those clinging to the folk music boom that boomed and went decades before and “For Your Consideration” hit also-ran actors where they live in the delusions and artifice of “awards season.”

But something about “Best in Show” resonated then and resonates still — the Western world’s love of dogs and how ridiculous people can get by “competing” such critters in glorified beauty and breeding pageants.

Williard goes for an improvised but polished laugh with every line, and scores constantly.

“I went to one of those obedience places once…It was all going well until they spilled hot candle wax on my private parts.”

Coolidge, Lynch, Levy, Bob Balaban (as the club’s president), Higgins and McKean all land their share of ironic laughs. Their commitment shows in every scene, with none more committed than indie icon Posey, who had braces put on which she wore for the entire shoot, completing her shallow, vain character’s reasons for neurotic self-debt.

But O’Hara steals the picture with just her presence — rolling with every “THIS is my HUSBAND” she has to remind every piece of her past that approaches her with lust in his eye. She makes Cookie a classic Florida “type” — fiftyish, busty and with a past as “busy” as any woman who would choose to wear her paste-on name tag on her chest and not the sweater that covers part of it.

Carry on, Westminster. And carry on Cate, one of the greatest ensemble comediennes ever to improvise a laugh.

Whatever we didn’t love about the last “Spinal Tap” movie, Guest will always have “Best in Show” in his introductions and some day — hopefully in the DISTANT future — leading his off his obituary.

This time, they touched a nerve and hit close to hole. And with every over-sexualized cringy laugh, they made ensembles “in” and something worth making ironic merriment with, on the big screen or in “The Office.” .

Cast: Catherine O’Hara, Eugene Levy, Parker Posey, Jane Lynch, Jennifer Coolidge, Bob Balaban, John Michael Higgins, Michael McKean and Fred Willard.

Credits: Directed by Christopher Guest, scripted by Guest and Eugene Levy. A Castle Rock/Warner Bros. release on Pluto, Netflix, other streamers.

Running time: 1:31