Manna Nichols as Eliza Doolittle and Benedict Campbell as Henry Higgins in “My Fair Lady.” (Suzanne Blue Star Boy/Suzanne Blue Star Boy)

After listening to the luscious renditions of “I Could Have Danced All Night” and “On the Street Where You Live” in Arena Stage’s often tunefully adept if dramatically inert revival of “My Fair Lady,” you may never feel worthy of singing them in the shower again. Manna Nichols and Nicholas Rodriguez, the Eliza Doolittle and Freddie Eynsford-Hill of director Molly Smith’s new production, apply to their vocal performances a show-tune shimmer that does thorough justice to two of the musical’s beloved standards.

But the rush one experiences when these actors hit their high notes fails to flare at any other moment of this uninspired evening in Arena’s flagship Fichandler Stage. The sparkling score by Alan Jay Lerner and Frederick Loewe retains much of its fizz, courtesy of the 13-piece orchestra under Paul Sportelli’s crisp command. And here and there, a performer in costume designer Judith Bowden’s gorgeous Victorian finery and orchid-evoking hats shows us how it’s done, a feat accomplished most winningly by Catherine Flye, as a wry and wonderfully wise Mrs. Higgins.

Yet in the cockney numbers that should supply “My Fair Lady” with its earthy exuberance and, even more essentially, in the romantically charged war between flinty speech professor Henry Higgins (Benedict Campbell) and frisky flower girl Eliza, the show comes across as in need of nourishment. “Get Me to the Church on Time” can usually be counted on to give Act 2 its effervescence. Here, as presided over by James Saito’s utterly anemic Alfred P. Doolittle, the song runs out of steam as the ensemble runs around quite literally in circles.

Smith scored a noteworthy success with another American musical classic, the “Oklahoma!” that opened Arena’s refurbished home in the fall 2010 and proved such a smash that it was brought back the following summer. The freshness of that enterprise reflected Smith’s affinity for the musical’s hearty frontier spirit and for the common cause embodied by the rough-hewn types making their way in the burgeoning territories of a young nation.

With Shavian characters defined so consciously by class and manner — the 1956 musical is based on George Bernard Shaw’s “Pygmalion,” now being presented by the Washington Stage Guild — “My Fair Lady” does not readily yield to re-interpretation. Henry is an elitist and misogynist and Eliza is fiery and unschooled. When their edges become too soft, when you cannot fully credit Henry’s cruelty or Eliza’s rawness, the magic in the musical’s love and transformation stories is lost.

I didn’t buy for one minute the beautiful, refined Nichols as a guttersnipe in need of a makeover or the benignly professorial Campbell as a cold brute in Savile Row tailoring. That partly may explain why the first hour or so of this production is leaden; when this Henry sings “I’m an Ordinary Man,” the title words ring too true. In the long dialogue scenes between them, there’s no igniting of the flame. (When you’re bored, you begin noticing little things, as in, why do Campbell’s eyeglasses look as if they belong to an English academic circa 2009?)

It isn’t until the surefire “The Rain in Spain,” well-played by Campbell, Nichols and Thomas Adrian Simpson as Col. Pickering, that any musical energy is generated. Nichols runs with the buoyancy of that number for the famous solo that Lerner and Loewe smartly followed with, lickety-split: her “I Could Have Danced All Night” scales the evening’s highest peak. Soon enough, Rodriguez — the Curly of Smith’s “Oklahoma!” — arrives outside the Higgins townhouse on Wimpole Street to croon his blissfully full-bodied version of “On the Street Where You Live.” And to top off the evening’s most successful phase, Nichols’s Eliza materializes for her coming-out at the embassy waltz in a drop-dead ball gown by Bowden, made of silk chiffon with iridescent sequins.

The infusion of “Downton Abbey” chic finds no corresponding down-market panache in the have-not scenes of this “My Fair Lady.” Choreographer Daniel Pelzig seems to have found little to engage his imagination in the slums of London; the dance steps for the cockney chorus in “With a Little Bit of Luck” and later, in “Get Me to the Church on Time,” look perfunctory, and all that Saito’s peculiarly joyless take on Alfie Doolittle manages to do is give bacchanal-level carousing a bad name.

Campbell, who played this role for Smith in the “My Fair Lady” she staged at the Shaw Festival in Ontario in 2011, is a solid actor with a sharp ear for irony. Unlike the unforgettable Rex Harrison, who spoke-sang his way in the part to Broadway immortality — and won an Oscar for the 1964 film version — Campbell hews to the melodies. His voice is firm. But as with the unpersuasive roots of Nichols’s coarseness, this Henry has trouble convincing us that he’s not so nice.

Perhaps the impetus to muffle the character’s loud imperfections emanated from a discomfort with the magnitude of Henry’s woman-hating. “Why can’t woman be more like a man?” Henry sings late in the show in “Hymn to Him,” a number that was greeted in the Fich by the sound of crickets. Trailing along is Sherri L. Edelen’s Mrs. Pearce, the vigilant housekeeper, making faces at him behind his back. Too often on this evening, crinkling one’s nose does seem an apt reaction.

My Fair Lady

Book and lyrics by Alan Jay Lerner, music by Frederick Loewe. Directed by Molly Smith. Choreography, Daniel Pelzig; music director, Paul Sportelli; sets, Donald Eastman; costumes, Judith Bowden; lighting, Jock Munro; sound, Carl Casella; wigs, Anne Nesmith; dialect coach, Kim James Bey. With Thomas Adrian Simpson, Sherri L. Edelen, Benjamin L. Horen, Rayanne Gonzales, Ronald Duncan, Kurt Boehm. About 2 hours 45 minutes. Through Jan. 6 at Arena Stage, 1101 Sixth St. SW. Call 202-488-3300 or visit