The Boston Symphony Orchestra took to the Carnegie Hall stage replete with red rose boutonnières, an expression of Boston gentility perhaps or possibly solidarity with Andris Nelsons, also sporting a rose, their outgoing music director. Their time-honored burnished sound would tackle three scenes from John Adams’ Nixon In China, arranged by Adams especially for the ensemble, before settling into Dvorak’s beloved Symphony No. 9, better known as From the New World.

Adams’ first opera remains as sumptuous and trailblazing as the day of its 1987 premiere at the Houston Grand Opera. Its perennial newness, incorporating rhythmic and probing cadences, is genuinely thrilling, even in this brief excerpted form. Appropriately enough it opened with Act I, Scene 1, sung by the formidable Tanglewood Festival Chorus under the direction of Lisa Wong. This is a hair-raising compendium, especially considering its pedantic subject matter, consisting of Mao Zedong’s Three Main Rules of Discipline and Eight Points of Attention. Adams and librettist, Alice Goodman are fearless out of the gate.

Resplendent in a red gown, Renée Fleming grasped Pat’s uncertainty and awe at her surroundings. She conveyed lovely touches of grace in Act II, Scene 1 “This is prophetic!,” in which she reacts to her curated tour of Beijing’s important historical and cultural sites. Fleming’s Pat, though timid, soars convincingly over chorus and orchestra. She is a force, if not to be reckoned with, at least providing the proceeding with soft power and compassion. Fleming continues to enhance her legendary status with a lush soprano and astute characterizations.

We revert to Act I, scene 3, in which Nixon speaks at a state banquet about the prospect of mutual understanding and the worldwide reach of his visit via modern technology. The chorus supports him with cries of “cheers.” Thomas Hampson, who can be forgiven for evoking Thomas Jefferson with his silver mane and imposing demeanor, turns his rich and resonant baritone on to Nixon’s beleaguered anxiety. Supported only by his political arrogance and that pathetic V for Victory gesture, his Nixon appeared to disintegrate before us. Adams and Goodman create a revealing frenzy out of what was actually a static political ritual.

Fleming and Hampson are obviously a dream cast and collectively the three scenes become the classiest expression ever of the P.T. Barnum quote, “Always leave them wanting more.” We do — and would be grateful for a concert staging knowing that we had not heard the sad dignity of Chou En-Lai’s reflections or the electrifying aria, “I am the wife of Mao Tse-tung,” two thrilling moments in a work of genius filled with them.

Genius though it may be, Adams’ music doesn’t take care of itself and in fact requires a conductor who adheres to the discipline of its tight construction and pulsating momentum. Nelsons, to his credit, was a respectful presence, pushing the orchestra, in all of its glorious refinement, to bring out the music’s splendor and depth.

That he reverted to florid showmanship for the Dvorak was simply distracting. Symphony No. 9 is a beguiling work, foundational in that it has brought many an ear to classical music. It is atmospheric, accessible and not overtly programmatic. And along with its quoting of Black spirituals and the influence of Native American lore, it contains melodic invention, most notably the melody assigned to the English horn at the beginning of the largo movement. This would become “Goin’ Home,” when his student, William Arms Fisher penned lyrics. While the symphony survived Nelsons’ approach, it felt segmented throughout as if he were conducting isolated scenes delineated by unnecessary gesture.