Her achingly pinpointed pitches, but one example of her involvement in the songs as well as of her preeminent musicality, took fire as soon as she sounded them — for example, in Duparc's “Au pays où se fait la guerre” (To the war-torn land) — and that fire blazed to the fullest in the rich harmonies of the final refrain, “Et moi toute seule en ma tour/J'attends encore son retour (And, all alone in my tower/ I yet await his return). Martin Katz, her accomplished, experienced pianist, caught fire a little himself: his passagework here seemed positively Liszt-ian.

Sibelius, Mattila's countryman, was represented by one icily beautiful song in Finnish, “Illalle” (To Evening) and five in Swedish. “Norden” (The North) hovered in wonderfully chilly irresolution until the final cadence brought it home to an almost unwelcome warmth. The text of “Flickan kom ifrån sin älsklings möte” (A girl came home from her lover's tryst) reads like a simple folk song on the theme of infidelity, but Mattila's treatment was appropriately heart-rending. The final two songs, “En slända” (A dragonfly), a strangely magical song full of odd, foreshortened melismas, and “Var det en dröm?” (Did I just dream?) were revelations. Mattila followed the dragonfly's progress as it flew away at the end (“We forgot that you were sun, I only shadow”) with longing eyes, slowly, reluctantly turning her head upstage to watch it flying to its home behind the piano. The wild passion of the climax of the last song threatened to bear both singer and pianist to some other world.

Rachmaninoff began the second half, occasioning a costume change for Mattila from red silk to sleeveless black. Memorable among the five songs in the set were the last three — not only because of the beauty and excitement of the songs themselves but also because of the connections between them. “Otrï vok iz A.Myusse” (Loneliness [Fragment from De Musset]) ended in a no-holds-barred “O odinochestvo, o nishcheta!” (Oh loneliness, oh poverty!), followed, as if in answer, by the consolation of “Muza” (The Muse). Mattila sang the gorgeous last few lines full out with her hand raised piteously to her head as the muse takes the flute from the hands of the musician and brings it to life: “And my heart was filled with divine enchantment.” And finally came the complete surrender to love, “Kakoye schast'ye” (What happiness), in which the singer, personifying ecstasy, shook with the effort of resonating every fiber of her body. Once again the pianist matched her fervor.

Selections of the “Gypsy Songs” of Dvořák seemed an impossible task both to perform and to absorb after that maelstrom. But Mattila is an artist of seemingly unlimited imagination and resourcefulness. After returning to the stage wearing a little transparent, gypsy-ish jacket over the black dress and still panting from her previous exertions, she gave her most physically active performance yet, stamping her feet like a gypsy and gesturing with abandon. Using both outstretched arms, she simultaneously pointed to the pianist with one arm and silenced the audience (which had been applauding after every song throughout the concert) with the other. Bound to the songs by her unflagging artistry, she gave an illuminating, commanding portrayal of the fierce love of freedom, the resignation and sadness, and the scorn for wealth and society that comprise gypsy lore.

For her first encore, Mattila returned wearing a colorful scarf and no shoes, carrying a pair of golden earrings in her hands, to sing “Golden Earrings,” a forgettable song from the forgettable 1947 movie of the same name in which Marlene Dietrich sang it. Mattila vamped the audience, playing broadly to the tiers, then announced with a toss of her head that she wanted to do it again “in my own language.” (Her English diction had been perfect.) This time she vamped the pianist, draping herself around him on the piano bench. Then, putting on her shoes and tossing her scarf upstage, she sang an amusing Finnish folk-song about a very small lover, “Minuri Kultani Kaunis On” (roughly, My Darling Beautiful, Is”), turned to Katz and laughed heartily. And so did he. Happy performers. Happy audience.