Like a play dominated by a character who never appears, Friday's Ordway Center program by the St. Paul Chamber Orchestra moved within the gravitational field of "Tristan and Isolde," Richard Wagner's seminal opera of frustrated desire, completed in 1859.

Different as they are, Wagner's "Wesendonck" songs and Arnold Schoenberg's "Transfigured Night" can both be heard as footnotes to "Tristan." (Two of the songs served as "studies" for the opera; an early critic waggishly suggested that Schoenberg's score sounded as though someone had smeared the still-wet ink of "Tristan.")

And if on Friday Wagner's songs -- transformative settings of five banal poems by Mathilde Wesendonck, a married woman with whom the married composer was infatuated -- made a deeper impression than Schoenberg's 1899 opera-without-words, the explanation is simple: Christine Brewer, in sumptuous voice.

One of the world's reigning dramatic sopranos, Brewer has triumphed in the most demanding roles of Strauss and Wagner, including Isolde. She also is a captivating recitalist. Her glowing account of the "Wesendonck" songs entwined both these strands of her career; her singing was lustrous and powerful, tender and vulnerable by turns. There was nothing of the diva about her. Her German -- unfailingly intelligible yet never over-articulated --was a joy. Together with conductor Ward Stare, who lit up the felicities of Felix Mottl's orchestration, Brewer reminded listeners that Wagner isn't exclusively a creature of the opera house.

"Transfigured Night," last essayed by the SPCO a quarter-century ago, fared less well. Though played on a frigid evening that could have used some serious transfiguring, the music -- as close as Schoenberg ever came to popular success -- remained stubbornly earthbound, even in its radiant coda. Steven Copes' solos were a high point: like so many distinguished American violinists, the SPCO's concertmaster studied with Felix Galimir, who, as a young man in Vienna, was a member of the Schoenberg circle. But Stare's conducting lacked suppleness and fire, at times allowing the work's narrative line to sag.

The program began, none too auspiciously, with Mozart's Symphony No. 17, in a reading that might have traded some of its abundant energy for a bit of elegance. The qualities we think of as Mozartian were more evident in Beethoven's mercurial "Ah, Perfido!" -- a virtuoso vehicle for Brewer, who negotiated it impressively.