PROVIDENCE – When you’re The New Kids on the Block and you’re not new and you’re not kids and you haven’t been on the block for a decade and a half, your options are a) learn the old steps, sound as much like the records as you still can and hope no one notices the alternating staleness and rust, or b) if there were more classic skills and appeal in your singing and your material than you got critical credit for, you can let them ride. Fortunately, last night at the Dunkin’ Donuts Center, the Boston quintet, one of the platinum-selling forerunners of the boy-band movement, mainly stuck to the latter.

Starting off with the new “Single,” from this year’s reunion album The Block, was the first sign that even though the show may have been a nostalgia trip for most of the fans, the New Kids were taking this seriously. The energy with which they then immediately powered through the back-in-the-day “My Favorite Girl” and the G-rated Prince funk of the classic “The Right Stuff” was the next.

The live setting was good for them. The Block suffers from the kind of generic production that plagues a lot of older groups when they try to sound current, and so much of their older material had a party-like-it’s-1988 production that sounded dated right out of the box. But last night, for example, the opener “Single” took on new life in its live rendition, with real hollering from Joe McIntyre and real pounding from their four-piece band.

Throughout, the material’s (and the harmonies’) roots in Philadelphia soul showed through — the too-short snippet of “Didn’t I Blow Your Mind,” embarrassingly jejune on their debut record but silky and soulful last night, was the clincher, but even the mega-hit “I’ll Be Loving You Forever” had a classic tinge.

None of the New Kids’ voices has aged badly, and in some cases they’re singing better than ever. Jordan Knight’s falsetto on “My Favorite Girl” was suitably cooing, and Joe McIntyre managed to sound youthfully enthusiastic on “Please Don’t Go Girl.” And the dancing — a mix of classic soul-group with some hip-hop scruff, was still in place. (Of course, the oldest of them are only scraping 40 now, so maybe it’s no big surprise.)

While Donnie Wahlberg’s thug-with-a-heart-of-gold schtick was no more believable this time around than in the ’90s, particularly on “Games” (though Danny Wood’s break dancing was still impressive), he made a decently growly frontman on “Grown Man” (with video cameo from The Pussycat Dolls’ Nicole Scherzinger).

Two new songs, the plush ballad “Two in the Morning” and the weak funk of “Dirty Dancing,” and the old ballad “Tonight,” were done on a small rotating stage in the middle of the crowd. The three lead singers got solo spotlights — Knight on “Give It to You,” McIntyre on “Stay the Same” and Wahlberg on “Cover Girl.”

Wahlberg told the crowd “we probably would not have believed you” if they had been told in the ’90s that their appeal would last this long. Would they be packing the Dunk without the nostalgia factor? I don’t know whether we can say that (cf. the dated encores “Step by Step” and “Hangin’ Tough,” examples of genres and hybrids which have been much more effectively explored in recent years). But their Norma Desmond phase is a long way off.

Natasha Bedingfield preceded the New Kids, skipping and traipsing through her tuneful, mannered British pop-soul. Breezy Notting Hill grooves such as “These Words” and “Never Found a Love Like This” worked better than the attempts at grit such as “Angel.” And “Unwritten” was its usual gossamer self-help self, although it got a souped-up coda befitting its last-song status.

The dancehall diva Lady GaGa opened the show with a short set of electronic-laden dance-floor pounders as artificial, but also as confectionary and fun, as cotton candy.

rmassimo@projo.com