At his best, with plays such as “The Odd Couple,” Neil Simon has no rival when it comes to American stage comedies. At his worst, he has produced work so saccharine it should come with a warning label for diabetics.

And sometimes, one of his plays has a combination of Simon’s best and worst.

Plays such as “Brighton Beach Memoirs.”

This autobiographical 1983 comedy proved one of his biggest hits. It ran for 1,299 performances on Broadway and helped launch the career of Matthew Broderick, who won a Tony Award for his performance of the precocious Eugene.

Hilarious as the play may be — and it is ferociously funny — “Brighton Beach Memoirs” also wallows in some unforgivable sentimentality. There is nothing the Willows Theatre Company’s new production can do about that, so it compensates with brisk pacing, a beautiful set and a terrific cast led by teen actor David Beale, brilliant in the starring role.

“Brighton Beach Memoirs” runs at the Willows Theatre in Concord through April 20.

Simon’s tale of Eugene Jerome, a 15-year-old Jewish kid growing up in prewar Brooklyn with his poor but loving extended family, can’t help but resonate with audiences. Eugene’s world is a torrent of tsuris: His feisty older brother struggles with self-esteem; his parents battle the financial wolf at the door; his even poorer aunt and two female cousins reluctantly depend on the Jerome family for a roof over their heads.

In Act I, Simon unspools the subplots. Eugene’s secret crush, his 16-year-old cousin Nora, wants to run away to be a Broadway showgirl. Brother Stanley is an at-risk teen, what with his hot temper and urge to gamble. And the brewing tension between Eugene’s mother, Kate, and her dependent sister, Blanche, makes for the play’s most explosive moments.

Through it all, Eugene remains a charming island of calm. He nurses twin dreams of becoming a writer and/or a pitcher with the Yankees. The writer in him wins out, as Eugene engages in a running monologue, taking note of his family’s many quirks.

Though Jewish, the family tries hard to assimilate into American culture. But Old World ways die hard. Remembering the Irish goons that beat up Jewish kids in the neighborhood, Kate mistrusts the Irish family next door. Thoughts of the family’s cousins in Poland weigh heavily as the storm clouds of war gather back in Europe.

Director Richard Elliott adds a nice touch, having the cast members kiss an imaginary mezuzah on their way into the house (though one wonders how many non-Jews in the audience understood).

As brother Stanley, Aaron Wilton whips up a tightly coiled pugnacity, providing a perfect foil to Eugene’s benign wit. A scene in which Stanley shares with his kid brother the secrets of sex is easily the play’s funniest, thanks to the actors’ Abbott-and-Costello-like delivery.

Because Beale (as Eugene) is so naturally endearing, the play tends to sag whenever he is offstage, though every character has time to shine. Val Hendrickson is superb as Jack, a Lomanesque salesman barely able to provide for his family. “When does it get easier?” he asks rhetorically. Of course, it never does.

Cindy Goldfield’s Kate is also affecting as the do-it-all mom who starts to crumble in Act II.

Unfortunately, actress Christina Anselmo, who plays Kate’s sister, Blanche, had a serious problem with forgetting lines in one recent performance. Though otherwise excellent as the diffident Blanche, Anselmo nearly wrecked the show with her stumbling.

Even worse are Simon’s slips into the maudlin. If the mantra of “Seinfeld” producers was “No hugging, no learning,” Neil Simon goes 180 degrees in the opposite direction in “Brighton Beach Memoirs.” The climax of the play is a cascade of confessions, apologies and emotional growth. It’s almost like an episode of “Full House.”

Still, with young Beale in command, the play never runs aground. He’s fearless, funny and loveable as Eugene. And as much as his character is clearly on his way to the top, one can’t help feeling certain the same is true for David Beale.

“Brighton Beach Memoirs” plays Wednesday-Sunday through April 20 at the Willows Theatre Company, 1975 Diamond Blvd., Concord. Tickets: $30-$40. Information: (925) 798-1300, or www.willowstheatre.org.