Yannick Nézet-Séguin leads two orchestras in Mahler's Symphony No. 8 in Ottawa

OTTAWA - Since he's neither tall nor old, conductor Yannick Nézet-Séguin jokes that he sometimes feels like a kid trying to tame 100 lions onstage.

On Wednesday at the National Arts Centre here, the Philadelphia Orchestra's new music director-designate had nearly 500 such musical beasts for Mahler's Symphony No. 8 ("Symphony of a Thousand") positioned in balconies, in boxes, and onstage, with an adoring audience that included Canada's governor-general (the surrogate for the queen of England), Michaëlle Jean. The concert combined forces from Montreal and Ottawa, both choral groups and the musicians of Nézet-Séguin's Orchestre Metropolitain du Montreal and the National Arts Centre Orchestra, whose music director, Pinchas Zukerman, attended.

Yes, the joining of Canada's Anglo and Franco strains was of underlying significance. But there didn't seem to be anything under the surface of the praise showered on Nézet-Séguin: In a preconcert ceremony, he received the $25,000 National Arts Centre Performing Arts Award - an honor reserved for the original and the accomplished, such as director Robert Lepage and Cirque de Soleil.

A peak moment in his Canadian profile? Undoubtedly. The prestige of the award was heightened by Sunday's news that he will become Philadelphia's music director in 2012, an appointment that clearly has prompted a renewed appreciation for this native son. When his institutional commitments were enumerated during the award ceremony, mention of "l'Orchestre Philadelphie" caused one audience member to blurt, "Wow!" No worries about losing him completely, though; at a postconcert reception, the conductor made a ringing commitment to future work with his Montreal orchestra.

With a symphony as imposing as Mahler's 8th, there was no chance the music would get lost amid the celebration. Though not necessarily his greatest, it commands attention like none other, and is so expensive to mount that it's heard infrequently.

Nézet-Séguin's reputation for speed was definitely confirmed in the symphony's 25-minute Part One, the Bach-on-steroids "Veni, Creator Spiritus," with orchestra and chorus pushed hard and often to thrilling effect. Yet like a cathedral facade, this work is full of porticos, each of which was given a distinctive character and tempo.

The performers had a lot to handle during this temporary musical alliance, in which the two orchestras' string sections (excellent individually) hadn't entirely jelled or found a collective personality in sound. Ensemble was occasionally unstable, and the excitement of the occasion drove some vocal soloists into vibrato overdrive. But it must be said that, even at full cry, the choral/instrumental sound never felt forced and often achieved moments of great ethereal beauty - between a succession of incredulity-inducing climaxes, each outdoing the last.

Part Two sets to music the esoteric final scene of Goethe's Faust, which has various angels, blessed creatures, and religious philosophers holding forth about matters of great profundity, and which can seem opaque in a less-than-savvy performance. Nézet-Séguin had all sorts of original responses to Mahler's imaginative scoring, such as the particularly tight blend of male choristers and cellos. The effect was disturbing, eerie, otherworldly, and extremely effective. Certain sections will always let you down, such as the vocal entrance of Mater Gloriosa (the Blessed Virgin Mary), which should be sublime but feels like more of the same. However, the overall architecture and momentum of the performance carried the music handily. Soloist vibratos were tamed, with mezzo-soprano Susan Platts delivering her characteristically earth mother, Kathleen Ferrier-ish sound, which anchored all the text's philosophical musings.

Though the night was grand, Nézet-Séguin was not. At the postconcert reception, he joked about how conducting such a complicated symphony with the large award medallion bouncing around his neck could have knocked out his teeth. During bows, he was seen moving some of the singers' water bottles so nobody would trip. And at rehearsals, he was heard puzzling over one of Mahler's violin bowing marks, and murmured, "I'll have to ask him about that some day - but not for awhile."