By Thor Christensen

As far as white soul singers go,nobody's going to confuse Boz Scaggs with Van Morrison. And as a blues guitarist, the Dallas-raised rocker doesn't exactly keep B.B. King up at night worrying.

Yet for a guy most people dismiss as a two-hit wonder from the '70s, Mr. Scaggs showed surprising depth Friday night at Coca-Cola Starplex, where he opened for Stevie Nicks.

Mr. Scaggs waited until the end of his hourlong set to deliver his two big hits - "Lowdown" and "Lido Shuffle" - but his most intriguing stuff came earlier on. With Hammond B-3 player Scott Plunkett pouring out gospel-drenched organ notes behind him, Mr. Scaggs cut to the heart of R&B and Memphis blues and stirred in some Spanish-flavored pop for good measure.

His smooth soul singing was fine -that is, when he wasn't overplaying the marbles-in-his-mouth effect - but what really made his set was his tough, understated guitar work - one part Chicago blues, one part cool West Coast jazz.

A few of his tunes came off as dated - especially "Look What You've Done to Me," his gooey ballad from the Urban Cowboy soundtrack - and that synth line in "Lido Shuffle" sounded downright goofy 22 years after the fact. But Mr. Scaggs' soaring guitar in "Lido" sounded just as convincing as the triumphant chorus, which had the whole crowd singing, "Woh-oh-oh-OH!" He wisely downplayed the disco flourishes of "Lowdown" and instead turned it into a fiery Afro-Latin bass-and- percussion jam.

But as Mr. Scaggs pointed out, he was just warming up for the headliner, Ms. Nicks, who's enjoying a career renaissance these days.

Five years ago, she'd have been hard-pressed to fill a 3,000-seat theater, but suddenly everyone wants to see Ms. Nicks and get in touch with their inner witch. On Friday night, a crowd of 10,000 hung on her every costume change, of which there were many, and her every twirl dance, which were fewer and slower than in years past. Chalk up part of her resurgence to the fact that everyone from Courtney Love to Tori Amos to the Smashing Pumpkins has been covering her tunes lately. Fleetwood Mac's recent reunion tour and album didn't hurt her popularity either.

Of course, she trotted out several Mac staples - "Rhiannon," "Gold Dust Woman" and "Dreams." But the most interesting moments arrived when she also dared to sing obscure tunes, such as during an acoustic segment made up of tunes she wrote about Hollywood: "Garbo," "You Never Promised Me a Rose Garden" and the country-flavored "After the Glitter Fades."

Every now and then, Ms. Nicks sounded hoarse and winded and relied heavily on her two female backing singers. But compared to a lot of her shows in the '80s - when drugs and wear and tear turned her voice into a raspy croak - she sang like a songbird Friday night.