"What with all the disco-oriented songs," Rod Stewart said to a sold-out Capital Center crowd last night, "I think it's time to make my statement." With that, he pulled out a harmonica and ground into a bump-and-blues version of "I just Wanna Make Love to You."

Stewart's recent multimillion selling work in the disco field has caused plenty of consternation among his longtime rock 'n' roll fans who saw Rod the Mod becoming the king of Studio 54. But Stewart has not defected; aside from the obvious disco numbers like "Da Ya Think I'm Sexy," Stewart's 90-minute show last night was a masterpiece of powerful, bawdy rock 'n' roll.

Stewart's singing career stretches back before disco through rock and pub rocks to the blues-weighted British rock of the '60s, and last night he set out to remind the audience of that history. The song list ranged from "Sweet Little Rock 'n' Roller" to "Maggie May" and "Get Back." The hardest hitting rock piece was a medley which careened from "I'm Losing You" to "Standing in the Shadows of Love" to "Layla" and finally an exhausting drum solo by Vanilla Fudge founder Carmine Appice.

Musically, the highlight of the show was a torchy rendition of Bill Wither's R & B classic, "If Lovin' You Is Wrong (I Don't Want To Be Right)." There was the Stewart who raised the blues-rock revolution to some of its highest moments.

As if Borg and Gerulaitas and Connors hadn't already proved it, Stewart put the final stamp on athletic chic, appearing in green basketball shoes, yellow eye shade and wrist bands and what would have been a warm-up suit if it had not been made of hot pink satin.