Portishead singer Gibbons stretches in lovely directions

As the lead singer of trip-hop heroes Portishead, Beth Gibbons has deservedly become one of the most celebrated vocalists in recent years. The empathetic way in which she conveys tales of yearning has put an indelible, 21st century spin on the torch song.

But her best work so far may well be the sublime new album, “Out of Season,” a collaboration with ex-Talk Talk bassist Paul Webb, who goes by Rustin Man for this project, which they wrote and produced together.

Out of the confines of Portishead and working with someone who clearly understands the range and beauty of her voice, Gibbons stretched her vocals considerably for the critically acclaimed album, taking them into the worlds of traditional jazz and folk.

On the last date of a brief U.S. tour Sunday at the Avalon, Gibbons and Webb, backed by a superb band that included Portishead’s Adrian Utley on guitar, turned those arrangements into pure elastic and displayed Gibbons as a singer of almost unparalleled prowess.

Like the album, the hourlong set was presented as a complete sonic journey. From the quiet beauty of the opening “Mysteries,” the five-piece group moved into the big-band feel of the jazzy and playful “Romance,” adding more musical layers with a swirling sound in the middle that wouldn’t have been out of place at a Portishead show.

In the live setting, Gibbons freely embraced the band that made her famous (and which she is still a part of), as in the soaring vocals and music at the end of the dramatic “Spider Monkey.”

But Gibbons, who jumped into the crowd after the show to shake hands and sign autographs, also had great fun shedding the Portishead image.

Accompanied only by an acoustic guitar, she delivered a stunning rendition of the moving “Resolve.” The moody, atmospheric “Funny Time of Year,” with Gibbons on guitar, ended in a Velvet Underground/Sonic Youth wall of sound. And the Velvet’s influence popped up again during an encore rendition of that band’s “Candy Says,” which Gibbons turned into a gorgeous mix of longing and hope.