He wasn’t about to let that happen twice. And you could see his point, because this event involved a sensational production. Almost every act could have been the “11 o’clock number” in any normal show.

Broadway icon Chita Rivera, in a stunning red sequinned pants suit, gave a zesty performance of “All That Jazz” from “Chicago” and teamed up with the legendary Tommy Tune for “Rosie” from “Bye Bye Birdie.” Ken Page, who got his start at the Muny before he played Old Deuteronomy in the original Broadway production of “Cats” , sang a tender rendition of that show’s biggest song, “Memory.”

The evening’s hosts, Broadway stars Matthew Morrison and Heather Headley, introduced the other artists and performed dynamic numbers of their own. Morrison led a highly condensed, 8-minute version of “Hairspray” while Headley soloed in a breathtaking medley of songs from “Funny Girl.”

Patrick Cassidy led a lively chorus of Muny Kids, Muny Teens and Muny veterans in “Trouble” from “The Music Man,” then presented a clip in which his mother, Muny Hall-of-Famer Shirley Jones, wished the theater happy birthday.

Two other Broadway stars, Graham Rowat and Jenny Powers, added elegance and comedy, respectively.

A big dance ensemble, choreographed by Michael Baxter, shone throughout, particularly when they joined Lara Teeter in a big tap treatment of “We’re in the Money” from “42nd Street” and in “Seize the Day” from “Newsies.”

Dennis Reagan, the Muny’s president and CEO, thanked “the best audience in the world” for its patience through the rain delays. Virtually everyone received generous applause, including the stagehands who mopped the stage after both cloudbursts. Paul Tarte dePoo III designed the versatile sets, Robin L. McGee designed the festive costumes and music director Michael Horsley led the generous Muny orchestra. Matt Kunkel directed the show, which kept a bright pace despite the weather.

For the last number a little before midnight, the audience enjoyed “One” and a fabulous fireworks display. In “A Chorus Line,” “One” is about a glamorous entertainer. But on Saturday night, it was unmistakably a song about the Muny.

Thousands more Muny lovers came to the Forest Park theater Sunday afternoon, where the celebration continued with lots of activities for families. The weather was lovely.