No composer portrayed carnal passion in all its ramifications as well as Wagner. That passion was clearly present in the fine performance by the Seattle Symphony on Thursday night under music director Ludovic Morlot. The concert was dedicated to Poncho, the 50-year-old Seattle arts organization that is now part of the Seattle Foundation.

Morlot began with the Prelude and “Liebestod” (“Love-death”) from Wagner’s opera “Tristan und Isolde”: the opera’s opening and then Isolde’s lament, which comes near the opera’s end. The two sections fit seamlessly together, and Wagner’s orchestration is so complete that the “Liebestod” is often performed as an orchestral piece without voice, as was done here.

It was a remarkable performance. A listener didn’t have to know the story to feel the moods portrayed — the yearning, the emotions, the hopes and the sadness in Morlot’s expansive, rich interpretation. The cellos set the feeling from the start, playing as one in an inexorably smooth flow of sound. As always, Morlot didn’t go overboard, though it can be easy to do that with Wagner. He allowed the music to speak for itself with the tensions and releases inherent within it. The orchestra followed his lead and the result was a wonderful exposition of the work.

Morlot continued with the Overture and “Venusberg” Music from another of Wagner’s operas, “Tannhäuser.” In this, Wagner’s writing is more frankly sensual, with much airy flitting around among the instruments, understandable as they represent nymphs and satyrs gamboling around a knight and goddess lying in each other’s arms. It’s astonishing how much of this Wagner is able to bring to mind though his music, and again Morlot brought it out superbly. It may be heresy to Wagner-lovers to say so, but he does tend to go on a bit too long. This music could have done with being a little shorter.

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The original order of the program was to have the Wagner works in the second half, and to open with Saint-Saëns’ “Organ” Symphony. Morlot chose to switch them, ending with the symphony; a good choice, as it would be hard to add anything after the magnificent triumphal end to its final movement.

Like Wagner, in this work Saint-Saëns believed that more is better, including the organ and even two pianists as part of the orchestration. The symphony ended with a grand but orderly explosion of sound with the organ, played by Joseph Adam, almost sounding like an orchestra by itself.

The orchestra, in its final concert of the Wyckoff Masterworks season, played with vitality, verve and precision, many of them with solos or as a section in a prominent part. Kudos go to principal oboe Ben Hausmann, who all through the evening played expressive solos, as well as to the other wind principals. Morlot recognized all the winds, brass and percussion by asking them to rise during the applause, followed by the strings. As usual, Morlot didn’t stand on the podium for applause, but beside the first violins.