SAN FRANCISCO -- When you come to this town as a DJ, you have to come correct.

This is the town that turntablist heroes the Invisibl Skratch Piklz call home. A city that houses Bomb Hip-Hop Records, the indie label that released the influential Return of the DJ album and scratch-fests by DJ Faust and Jeep Beat Collective. If you just stand up there and spin records, it won't be enough. And if you dare to cut, scratch and mix, you'd better have some impressive tricks up your sleeve.

On Friday night, big-beat artist DeeJay Punk-Roc (born Charles Gettis) and Barry Ashworth -- svengali of British electronica group Dub Pistols -- each experienced the challenge as they took turns manning the decks at the Justice League on the first night of a 20-city North American club tour. The 100 or so people who came to the show responded warmly to DeeJay Punk-Roc's mixture of old school hip-hop, electro-funk and mid-tempo club instrumentals, but began to filter out a bit once Ashworth came on and played songs with a repetitive, thundering techno beat.

DeeJay Punk-Roc is promoting his debut album, ChickenEye, which was released last year. Late last year, he promoted the album by playing between sets on the heavy metal-dominated Family Values tour. Ashworth, meanwhile, is celebrating the release of the Dub Pistols' Point Blank album, but is doing so without the rest of the current group lineup -- turntablist Malcolm Wax, guitarist John King, bassist Jason O'Bryan and keyboardist William Borez.

The evening started off with DeeJay Punk-Roc's set. Dressed in a New York Yankees baseball hat, orange jacket with brown stripes on the sleeves, and khakis, he set the tone for his genre-blending set with his first song. It was an Afrika Bambaataa-like electro-funk tune with a techno beat that incorporated the signature sample of James Brown screaming used on Rob Base and DJ E-Z Rock's hit "It Takes Two."

DeeJay Punk-Roc kept the electro-rap flavor going by playing a song that relied heavily on samples from Afrika Bambaataa and Soul Sonic Force's crucial "Planet Rock" track. He added scratches here and there to take the place of drum fills and also to remind the audience -- which, by then, had risen to its feet -- that he got his start as a DJ by playing block parties in the Bronx, N.Y., just like Bambaataa did.

The highlight of DeeJay Punk-Roc's set came early on, when he played Wildchild's "Renegade Master," a techno hit that relies heavily on an old-school rap vocal. At first, he didn't do anything to it, letting the fast-paced energy of the song stir the crowd into a dancing frenzy. Slowly, though, he altered the song by tweaking the pitch and the beat, sometimes incorporating a polyrhythmic approach by playing another record's beat underneath the original.

The coup, however, came during the vocal break from "Renegade Master." At the repeated phrase "Back once again it's the renegade master/Power to the people/With the ill behavior," DeeJay Punk-Roc turned down all the levels except the volume, giving the vocals a muddled, underwater sound. As the vocals continued repeating, he turned up the levels one at a time. When he turned up the final knob on the mixer, the beat kicked in, and the crowd cheered its approval.

"That was a great mix," Jennifer Wallace, 23, said following "Wildchild." "I've yet to see a crowd not react positively to that song, but he did some s--- to it that I've never heard before."

In the spirit of ChickenEye, the remainder of DeeJay Punk-Roc's set was a well-blended mix. Following "Renegade Master," he moved on to old-school rap chestnuts from Run-D.M.C. and Public Enemy. After that, he cut-and-scratched his way through a long block of techno and ambient music before closing things out with a remix of his own "I Hate Everybody" (RealAudio excerpt).

Between songs, he was friendly with the audience without resorting to the usual exhortations that "Somebody/anybody/everybody scream" or demanding that folks throw their hands in the air and "wave them like they just don't care." For that, he truly deserves some sort of award.

Lord knows where Barry Ashworth was during DeeJay Punk-Roc's set, but he should have been paying attention and taking notes. There's no doubt that the ska-techno blend of "Cyclone," the Dub Pistols' current single, is catchy and could spawn an electronica sub-genre, but the faceless, stereotypical techno music that Ashworth spun was far from groundbreaking.

Adding insult to injury, especially for a San Francisco crowd, Ashworth did little to manipulate the vinyl on his players. He only occasionally scratched, but never attempted to juggle his beats or recast a song using new music.

"This guy ain't got it," Mark Tucker, 21, said as he and his friends shuffled to the door midway through Ashworth's set. "I don't know what it is, really, but we're just not grooving to it."

Ashworth has a month of road work ahead of him, so perhaps he'll learn from his mistakes.

The tour continues Wednesday in Minneapolis and plays dates in the Midwest and on the East Coast before reaching New York on Feb. 27. From there, DeeJay Punk-Roc and Ashworth head west to such cities as Denver and Dallas, before playing a show March 11 in Hollywood, Calif., with Fatboy Slim. The tour then wraps things up in Jacksonville, Fla., March 13.