The Philadelphia Orchestra was visibly enjoying their evening at Carnegie Hall with Sir Simon Rattle, their frequent guest conductor who nearly became their music director. In a program of early modern classics and a perennial Beethoven favorite, energy and spirits were high and in good supply.

Webern’s Passacaglia is literally the composer’s opus one, before his style emerged into full-fledged serialism. The passacaglia is an ancient ground bass, or repeated pattern, providing a backdrop for variations in the melodic line. It was often used to accompany laments during the Baroque, and it is even used for the same purpose in pop music today. Webern writes his own repeated pattern, a spooky, sneaky string of eight plucked notes. This theme is embedded somewhere in the 23 variations of the piece, though dense harmonies and writhing textures dominate to form their own emotional arch. The Passacaglia may not offer a roadmap to Webern’s later embrace of atonality, but the work seems to wrestle with the legacy of Romantic harmony, fighting and twisting along the way. The fabulous Philadelphians brought listeners in with a hushed focus, and Rattle kept themes and gestures distinct, avoiding the pitfall of making the performance into a muddle.

Berg’s masterpiece opera Wozzeck illustrates a mature development of atonality, and the expressive possibilities that come with the departure from harmony. “Wozzeck is hardly easy listening”, we are told in the program notes. When will music that is nearly 100 years old stop being presented with this disclaimer? And what’s so enjoyable about easy listening anyway? Besides, any music that takes on murder, adultery, torture, and despair is not going to be music to fall asleep to, whether it’s “modern” music or not. The listener is better off not worrying about the “difficulty” of the Wozzeck fragments, or even wondering where we are in the plot. Best to just give ourselves over to the dissonances and prepare to be amazed by emotion captured in sound.

Our able guide was the inimitable Barbara Hannigan, whose wide-ranging talents are especially enjoyed in this repertoire. She led us through two extended soliloquies for Marie, the tragic anti-heroine, and the heartbreaking final scene, depicting Marie’s child after the mother’s murder. Without a touch of self-consciousness, Berg matches the expressive power of dissonance with an undulating, instinctive feel for form to depict human sadness with eerie precision. It was a beautiful, harrowing performance.

Ms Hannigan wore her leonine hair loose, an unusual but refreshing sight on the concert stage, and the auburn mane echoed a similarly-colored plume in her black dress. She surely must be one of the most trim and toned singers before audiences today, complete with arms worthy of Michelle Obama.

We were lucky to glimpse that fabulous hair, which Ms Hannigan hid under a black pageboy wig for Ligeti’s madcap, outrageous, and over-the-top Mysteries of the Macabre. That bob completed her secret agent look, which also featured a leather mini-dress and coat and Lady Gaga boots. The nine-minute scene (aria? Expostulation? Rant?), excerpted from the opera Le Grand Macabre, is Ms Hannigan’s calling card; to say she inhabits the piece vocally and physically is the understatement of the year. She creates a nervous character in perpetual motion, with even the tiniest flick of her pinky responding to the jerks and surprises of the music. Ms Hannigan is so capable of creating a range of colors with her singing that a listener is inclined to scan the ensemble to see if the instruments that she evokes (alternately flutes, oboes, celesta and more) are actually the ones making sound.

Singer and conductor palled around during the aria – which is set mostly to gibberish words and has a plot as convoluted as the rest of the opera – including at one point when Ms Hannigan booted Rattle off the podium for a little puppet-on-the-end-of-a-stick conducting. Perhaps alluding to Ms Hannigan’s recent foray into conducting herself? Rattle kicked her back off in a flash. The fireworks left listeners hungry for more.

Beethoven is often programmed on concerts of Second Viennese School composers. It can do service both as a palate cleanser, and a reminder of the fertile soils of Romanticism from which atonality sprouted. But after the zany theatrics of the Ligeti, the Pastoral Symphony fell a little flat. Lovely as ever, Rattle gave an elegant interpretation, and the orchestra clearly enjoyed playing the simple harmonies and lilting tunes. Things perked up a bit during the third movement Allegro–Presto (“Merry gathering of peasants”), when Rattle let the Philadelphians dig in and spurred on the tempo. By the end of the symphony it was as if we had spent a full day in the country. If just a bit haunted by atonal ghosts.