SPRINGFIELD - If you’ve ever been mellow, then Symphony Hall was the place to be that way Sunday night as Olivia Newton-John guided a willing crowd of 2,356 on a tour of her three-decade singing career.

Newton-John, her seven-member ensemble, and conductor-arranger Rick King joined the symphony in the opening Pops concert of its 2004-05 season.

Her sweet, supple soprano rang clear, despite having sung a show every night but one of the past seven, and she appeared genuinely delighted and perhaps a wee bit surprised at how warmly her many hits were remembered.

Songs and deftly arranged medleys from every facet of Newton-John’s performing life were speckled with sensibly brief and sincere chat, airing her charming Down Under accent. (Though she was born in England, Newton-John moved to Australia when she was 5.)

Vocal highlights included spot-on high B’s spiralling above a subdued, sultry acoustic samba version of her 1981 hit “Physical,” a poignant, subtle account of Arthur Hamilton’s “Cry Me A River” (in tribute to Julie London, for whom the song provided her only charted hit), and sweet, forthright reminiscences of what one might call her country-western phase, 1973’s “Let Me Be There” (her first Grammy-winner), “Please Mr., Please,” and “If You Love Me.”

Newton-John’s singing was solid and energetic throughout the program, but was often mixed frustratingly low in the overall soundscape, sometimes to the point where her middle voice was barely audible in the orchestra seats. Lithe and sparkling-eyed, she moved around the stage as if at least a couple of decades had been stripped from her 56 years.

As for repertoire, the ones the audience wanted were clearly the “Grease” songs, “You’re the One That I Want,” “Hopelessly Devoted to You,” and “Summer Nights.” These provoked a roar of approval and standing ovations from the front rows of Newton-John fans, who were clearly devoted to her.

Her band was very tight, obviously used to the routine and immune to missteps. Music director-guitarist Andy Timmons ran the show from stage-right, throwing in a few tasty Stratocaster licks in the bargain. Keyboardist Dane Bryant, bassist Lee Hendricks, drummer Dan Wojciechowski, and reed-man Warren Ham rounded out the ensemble.

Ham’s harmonica-work “Cry Me A River” and alto sax solo on “Physical” were noteworthy. He also served as backup vocalist and Travolta stand-in during some of the “Grease” numbers. Steve Real and Marlen Landin-Chapman turned in fine backing vocals and Real stepped to the foreground in a rich duet with Newton-John on “Suddenly” from the 1980 “Xanadu” soundtrack.

Conductor/arranger Rick King kept the orchestra on track through the arrangements in which it participated. One of the most beautiful, goosebump-raising moments of the evening was the French horn entrance in Newton-John’s gorgeous encore “I Honestly Love You.”

The least successful part of the show was a somewhat bland “rock” set including the Elton John-penned “Rumor,” Newton-John’s 1982 hits “Heart Attack” and “Make A Move On Me,” and 1979’s “A Little More Love” and “Deeper Than the Night.”

While the band was too loud for her to be heard, it was not loud enough to sell music, the sheer impact of which depends almost solely on its volume and insistence.

The symphony, which spent much of the second half listening or playing without being heard, got a brief chance to shine in the concert’s first half hour, led by guest conductor Neal Hampton through music associated with movie (and other) heroes from “Star Wars,” “Spiderman” and “Superman,” “Apollo 13,” to John Williams’ brass-busting Olympic music. Considering the scarily scant rehearsal time likely alloted to this not-so-easy repertoire, the orchestra acquitted itself admirably.