Pacific Northwest Ballet opened its season with a love letter to choreographer Twyla Tharp, reviving a cherished classic, and a zany, inventive treatise on classicism. Nine Sinatra Songs (1982) and Brief Fling (1990) flanked the world première of Waiting at the Station, an amiable story ballet set to an instrumental arrangement of songs by New Orleans R&B legend Allen Toussaint – played live by the PNB orchestra with the composer on piano. This rousing new work put the audience in a toe-tapping mood and looked like great fun for the dancers, but it lacks the dissident flair of Tharp’s more inspired creations.

Over the decades, Tharp has bulldozed the frontiers of dance, pioneered the concept of crossover, and influenced much of what is being done in dance today – from hip-hop to competition dance and avant-garde experiments in dance theatre. Her best work defies classification, poses the question “what turns movement into dance?” and mercilessly exposes the biases that dancemakers, audiences and critics bring to it. Sinatra and Fling do this brilliantly, and have stood the test of time – mirrored disco ball, punk-inspired Scottish tartans and all.

The Sinatra songs verge on the cheesy, but Frank turned them into poetry; similarly Tharp’s riffs on ballroom dance, both reverential and satirical, lift the form into high art. She fills in mellow, sonorous musical phrases with punchy acrobatics straight out of the boxing ring, then pours honey over the more percussive segments. Veering from the bluntly sexual ass-grabbing to the luscious, transporting waltz, the delicious and exacting tango parody, and the comic mistiming of inexperienced young lovers, Tharp reminds us of the ridiculousness of social conventions, and of our everlasting predilection for falling in love even though we are fully aware of the penalties.

PNB blessed us with a host of debuts in Saturday’s matinee – Leah Merchant and Ezra Thomson in “One For My Baby”, Ryan Cardea in “Somethin’ Stupid”, Elizabeth Murphy and Charles McCall in “All The Way” – all of whom grandly swept us up into their Oscar-de-la-Renta’d world, led by the superb Lesley Rausch and Joshua Grant in the opening “Softly As I Leave You”.

Brief Fling pits two castes of dancers against each other: the classicists in chic tartan tutus designed by Isaac Mizrahi, and the postmoderns – who look like they’d been awakened in the dead of night by a fire alarm and grabbed a random article of clothing before evacuating. Partially dressed in briefs and deconstructed tartan kilts, this gang, led by a splendid Leta Biasucci, wove in and out of the classical crew, accompanied by a crackerjack Greek chorus. The clash between the neoclassical and Tharp’s trademark, brazenly athletic movement, alternately slouchy and agitated, linked throughout by hints of folk dance, is intricately architected against a score by Michel Colombier that fuses Percy Grainger’s lilting English folk tunes, with a military tattoo and Colombier’s own electronic music, ominous and jarring. Lesley Rausch, with her eloquent upper body and vivid pointework, and the noble Jerome Tisserand shine in the lead classical roles.

With its formulaic narrative and stock Depression-era characters, Waiting at the Station came off as a highly polished backers’ audition for a Broadway musical.

Every dancer in this piece, from corps to principal ranks, showed charisma and chutzpah, and a dazzling command of Tharp’s explosive technique, ripping off traditional ballet jumps, turns and lifts at warp speed, often without conventional preparations, and with sudden changes of direction. Many phrases are quickly reversed – a tactic used mainly in ballet class to keep dancers’ minds razor-sharp, but Tharp uses it to “undress” technique, to startling, often magical, visual effect.

Interspersed with the electrifying allegro work, however, are far too many jazz clichés, all the slinky hip-swiveling and interminable Mardi Gras parading that eventually sink the piece.

Not even Santo Loquasto’s handsome set design for a 1940s small-town train station and meticulously detailed costumes that so convincingly evoke the hard circumstances and quiet disappointments of these working-class folk, nor James F. Ingalls’ smoky, atmospheric lighting, nor Toussaint’s brilliant piano-playing, can compensate for the lack of choreographic and storytelling imagination.

Notably superfluous is the trio identified in the program as Fates, clad unaccountably in shiny gold cigarette-girl-style dresses and gold shower caps, who pop up randomly to pester James Moore – very fine in the lead role – with a lot of busy but pointless bourrée-ing and leaping about. They inevitably invite comparison to the quartet of Fates in Christopher Wheeldon’s Cinderella, which premièred last season in a lavish co-production by San Francisco Ballet and Dutch National Ballet. Wheeldon’s Fates, bizarrely costumed in batik harem pants, masks and pirate bandanas, were a good deal less cheery than Tharp’s beaming maidens, but they too swooped in at the oddest moments to annoy Cinderella, more like mosquitoes than weighty allegorical figures.

Waiting at the Station avoids the tics and excesses of Tharp’s more muddled older work, but it leaves the faintest of impressions. The Saturday matinee audience disagreed with me, however, and leapt to their feet in admiration at the close.